Ni catalysts and methods for alkane dehydrogenation

ABSTRACT

Catalysts and methods for alkane oxydehydrogenation are disclosed. The catalysts of the invention generally comprise (i) nickel or a nickel-containing compound and (ii) at least one or more of titanium (Ti), tantalum (Ta), niobium (Nb), hafnium (Hf), tungsten (W), yttrium (Y), zinc (Zn), zirconium (Zr), or aluminum (Al), or a compound containing one or more of such element(s). In preferred embodiments, the catalyst is a supported catalyst, the alkane is selected from the group consisting of ethane, propane, isobutane, n-butane and ethyl chloride, molecular oxygen is co-fed with the alkane to a reaction zone maintained at a temperature ranging from about 250° C. to about 350° C., and the ethane is oxidatively dehydrogenated to form the corresponding alkene with an alkane conversion of at least about 10% and an alkene selectivity of at least about 70%.

This application is a continuation of U.S. patent application Ser. No.09/849,378, filed May 4, 2001, now U.S. Pat. No. 6,777,371, which is adivisional of U.S. patent application Ser. No. 09/510,458, filed Feb.22, 2000, now U.S. Pat. No. 6,417,422, which is a continuation-in-partof both, U.S. patent application Ser. No. 09/255,371, filed Feb. 22,1999, now U.S. Pat. No. 6,355,854 and U.S. patent application Ser. No.09/255,384, filed Feb. 22, 1999, now U.S. Pat. No. 6,436,871.

BACKGROUND OF THE INVENTION

The present invention generally relates to catalysts and methods foralkane or alkene dehydrogenation and specifically, to Ni-containingcatalysts and methods for oxidative dehydrogenation of alkanes oralkenes. The invention particularly relates, in preferred embodiments,to Ni oxide/mixed-metal oxide catalysts and methods for oxidativedehydrogenation of alkanes or alkenes, and especially of C₂ to C₄alkanes, and particularly, for oxidative dehydrogenation of ethane toethylene.

Ethylene can be produced by thermal cracking of hydrocarbons, bynon-oxidative dehydrogenation of ethane, or by oxidative dehydrogenationof ethane (ODHE). The latter process is attractive for many reasons. Forexample, compared to thermal cracking, high ethane conversion can beachieved at relatively low temperatures (about 400° C. or below). Unlikethermal cracking, catalytic ODHE is exothermic, requiring no additionalheat to sustain the reaction. In contrast to catalytic non-oxidativedehydrogenation, catalyst deactivation by coke formation is relativelyminimal in ODHE because of the presence of oxidant (e.g., molecularoxygen) in the reactor feed. Other alkanes can be similarly oxidativelydehydrogenated to the corresponding alkene.

Thorsteinson and coworkers have disclosed useful low-temperature ODHEcatalysts comprising mixed oxides of molybdenum, vanadium, and a thirdtransition metal. E. M Thorsteinson et al., “The OxidativeDehydrogenation of Ethane over Catalyst Containing Mixed Oxide ofMolybdenum and Vanadium,” 52 J. Catalysis 116–32 (1978). More recentstudies examined families of alumina-supported vanadium-containing oxidecatalysts, MV and MVSb, where M is Ni, Co, Bi, and Sn. R. Juarez Lopezet al., “Oxidative Dehydrogenation of Ethane on SupportedVanadium-Containing Oxides,” 124 Applied Catalysis A: General 281–96(1995). Baharadwaj et al. disclose oxidative dehydrogenation of ethaneand other alkanes using a catalysts of Pt, Rh, Ni or Pt/Au supported onalumina or zirconia. See PCT Patent Application WO 96/33149. U.S. Pat.No. 5,439,859 to Durante et al. discloses the use of reduced, sulfidednickel crystallites on siliceous supports for dehydrogenation andsuccessive oxidation of alkanes. Schuurman and coworkers describeunsupported iron, cobalt and nickel oxide catalysts that are active inODHE. Y. Schuurman et al., “Low Temperature Oxidative Dehydrogenation ofEthane over Catalysts Based on Group VIII Metals,” 163 Applied CatalysisA: General 227–35 (1997). Other investigators have also considered theuse of nickel or nickel oxide as catalysts or catalyst components foroxidative dehydrogenation. See, for example, Ducarme et al., “LowTemperature Oxidative Dehydrogenation of Ethane over Ni-basedCatalysts”, 23 Catalysis Letters 97–101 (1994); U.S. Pat. No. 3,670,044to Drehman et al.; U.S. Pat. No. 4,613,715 to Haskell; U.S. Pat. No.5,723,707 to Heyse et al.; U.S. Pat. No. 5,376,613 to Dellinger et al.;U.S. Pat. No. 4,070,413 to Imai et al.; U.S. Pat. No. 4,250,346 to Younget al.; and U.S. Pat. No. 5,162,578 to McCain et al.

Although nickel-containing catalysts are known in the art for alkanedehydrogenation reactions, none of the known nickel-containing catalystshave been particularly attractive for commercial applications—primarilydue to relatively low conversion and/or selectivity. Hence, a needexists for new, industrially suitable catalysts and methods havingimproved performance characteristics (e.g., conversion and selectivity)for the oxidative dehydrogenation of alkanes.

SUMMARY OF INVENTION

It is therefore an object of the present invention to provide for new,industrially suitable catalysts for oxidative dehydrogenation of alkanesto the corresponding alkenes.

Briefly, therefore, the invention is directed to methods for preparingan alkene, and preferably a C₂ to C₄ alkene, such as ethylene, from thecorresponding alkane, such as ethane. In general, the method comprisesproviding the alkane (or substituted alkane), and preferably the C₂ toC₄ alkane (or substituted C₂ to C₄ alkane) and an oxidant to a reactionzone containing a catalyst, and dehydrogenating the alkane to form thecorresponding alkene. The oxidant is preferably a gaseous oxidant suchas molecular oxygen, and is preferably provided, for example, as oxygengas, air, diluted air or enriched air. The alkane is preferablyoxidatively dehydrogenated. The reaction temperature is preferablycontrolled, during the dehydrogenation reaction, to be less than about325° C., and preferably less than about 300° C.

The catalyst comprises, in one embodiment, (i) a major componentconsisting essentially of Ni, a Ni oxide, a Ni salt, or mixturesthereof, and (ii) one or more minor components consisting essentially ofan element or compound selected from the group consisting of Ti, Ta, Nb,Co, Hf, W, Y, Zn, Zr, Al, oxides thereof and salts thereof, or mixturesof such elements or compounds. The catalyst preferably comprises Nioxide and one or more of Ti oxide, Nb oxide, Ta oxide, Co oxide or Zroxide.

In another embodiment, the catalyst comprises a compound having theformula I,Ni_(x)A_(a)B_(b)C_(c)O_(d)  (I), whereA is an element selected from the group consisting of Ti, Ta, Nb, Hf, W,Y, Zn, Zr, Al, and mixtures of two or more thereof, B is an elementselected from the group consisting of a lanthanide element, a group IIIAelement, a group VA element, a group VIA element, a group IIIB element,a group IVB element, a group VB element, a group VIB element, andmixtures of two or more thereof, C is an alkali metal, an alkaline earthmetal or mixtures thereof, x is a number ranging from about 0.1 to about0.96, a is a number ranging from about 0.04 to about 0.8, b is a numberranging from 0 to about 0.5, c is a number ranging from 0 to about 0.5,and d is a number that satisfies valence requirements.

In a further embodiment, the catalyst comprises a compound having theformula (II)Ni_(x)Ti_(j)Ta_(k)Nb_(l)La*Sb_(r)Sn_(s)Bi_(t)Ca_(u)K_(v)Mg_(w)O_(d)  (II),whereLa* is one or more lanthanide series elements selected from the groupconsisting of La_(m), Ce_(n), Pr_(o), Nd_(p), Sm_(q), x is a numberranging from about 0.1 to about 0.96, j, k and l are each numbersranging from 0 to about 0.8 and the sum of (j+k+1) is at least about0.04, m, n, o, p, q, r, s and t are each numbers ranging from 0 to about0.1, and the sum of (m+n+o+p+q+r+s+t) is at least about 0.005, u, v andw are each numbers ranging from 0 to about 0.1, and d is a number thatsatisfies valence requirements.

In still another embodiment, the catalyst comprises (i) a Ni oxide, and(ii) an oxide of an element selected from the group consisting of Ti,Ta, Nb, Co, Hf, W, Y, Zn, Zr, and Al, and the alkane is dehydrogenatedto form the corresponding alkene with an alkane conversion of at leastabout 10% and an alkene selectivity of at least about 70%. Ethaneconversion is preferably at least about 15% and more preferably at leastabout 20%. Ethylene selectivity is, in combination with any of thepreferred conversion values, preferably at least about 80%, and morepreferably at least about 90%.

In one embodiment, the catalyst is a calcination product of a catalystprecursor composition comprising (i) Ni, a Ni oxide, a Ni salt ormixtures thereof, and (ii) an element or compound selected from thegroup consisting of Ti, Ta, Nb, Co, Hf, W, Y, Zn, Zr, Al, oxides thereofand salts thereof, or mixtures of such elements or compounds.

In yet another embodiment, the alkane is co-fed to a reaction zone withthe corresponding alkene, such that the alkane is dehydrogenated to formthe alkene in a reaction zone comprising the corresponding alkene in amolar concentration of at least about 5%, relative to total moles ofhydrocarbon. The alkane conversion in such embodiment is preferably atleast about 5%, and the alkene selectivity is preferably at least about50%. In a preferred approach, the alkane dehydrogenation is effected ina multi-stage reactor, such that the alkane (or substituted C₂ to C₄alkane) and gaseous oxidant are fed to a first reaction zone containingthe catalyst, the alkane is dehydrogenated therein to form thecorresponding alkene, the product stream comprising the correspondingalkene and unreacted alkane are exhausted from the first reaction zoneand then fed to a second reaction zone, together with additional,supplemental gaseous oxidant, and the alkane is dehydrogenated to formthe corresponding alkene in the second reaction zone.

The invention also directed to nickel-containing mixed-metal oxidecompositions and catalysts, as characterized above, and to methods forpreparing the same.

Such catalysts and methods have advantageous performance characteristicsfor oxidative dehydrogenation of alkanes to their corresponding alkene,and particularly for dehydrogenation of unsubstituted or substituted C₂to C₄ alkanes to the corresponding alkene(s). The conversion,selectivity, space velocity, catalyst stability and reaction temperaturefor oxydehydrogenation of ethane to ethylene are particularlyattractive.

Other features, objects and advantages of the present invention will bein part apparent to those skilled in art and in part pointed outhereinafter. All references cited in the instant specification areincorporated by reference for all purposes. Moreover, as the patent andnon-patent literature relating to the subject matter disclosed and/orclaimed herein is substantial, many relevant references are available toa skilled artisan that will provide further instruction with respect tosuch subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A and FIG. 1B are schematic representations of exemplary reactionsystem configurations, specifically involving product stream recycle(FIG. 1A) and multi-stage reaction zones (FIG. 1B).

FIG. 2A and FIG. 2B are graphs showing ethane conversion (open circles)and ethylene selectivity (closed circles) data versus time on streamduring the 400 hour lifetime test in the parallel fixed bed reactor at275° C. for Ni_(0.75)Ta_(0.28)Sn_(0.03)O_(x) (FIG. 2A) andNi_(0.71)Nb_(0.27)Co_(0.02)O_(x) (FIG. 2B).

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, an alkane or alkene is oxidativelydehydrogenated over a nickel catalyst to form one or more correspondingalkene(s) or dialkene, respectively, and water. The oxidativedehydrogenation reaction can be represented (for alkane reactants) as:C_(n)H_(2n+2)+½O₂→C_(n)H_(2n)+H₂O

The catalysts of the invention generally comprise (i) nickel or anickel-containing compound and (ii) at least one or more of titanium(Ti), tantalum (Ta), niobium (Nb), cobalt (Co), hafnium (Hf), tungsten(V), yttrium (Y), zinc (Zn), zirconium (Zr), or aluminum (Al), or acompound containing one or more of such element(s).

In one embodiment of the invention, the nickel catalyst comprises (i)Ni, a Ni oxide, a Ni salt, or mixtures thereof as a major component, and(ii) an element or compound selected from the group consisting of Ti,Ta, Nb, Co, Hf, W, Y, Zn, Zr, Al, oxides thereof and salts thereof, ormixtures of such elements or compounds as one or more minor components.As used herein, the “major component” is the component of thecatalytically active compound or composition having the highestconcentration on an atomic basis. “Minor components” are components ofthe catalytically active compound or composition that do not have thehighest concentration on an atomic basis. In general, one of theaforementioned metal components may be present as in elemental form, asan oxide, and/or as a salt depending on the nature and extent ofcalcination.

The major component of the catalyst preferably consists essentially of aNi oxide. The major component of the catalyst can, however, also includevarious amounts of elemental Ni and/or Ni-containing compounds, such asNi salts. The Ni oxide is an oxide of nickel where nickel is in anoxidation state other than the fully-reduced, elemental Ni° state,including oxides of nickel where nickel has an oxidation state of Ni⁺²,Ni⁺³, or a partially reduced oxidation state. The Ni salts can includeany stable salt of nickel, including, for example, nitrates, carbonatesand acetates, among others. The amount of nickel oxide (NiO) present inthe major component is at least about 10%, preferably at least about20%, more preferably at least about 35%, more preferably yet at leastabout 50% and most preferable at least about 60%, in each case by molesrelative to total moles of the major component. Without being bound bytheory not specifically recited in the claims, the Ni and/or Ni oxideacts as a redox-active metal center for the oxydehydrogenation reaction.

The one or more minor component(s) of the catalyst preferably consistessentially of an element or compound selected from the group consistingof Ti, Ta, Nb, Co, Hf, W, Y, Zn, Zr, Al, oxides thereof and saltsthereof, or mixtures of such elements or compounds. The minorcomponent(s) more preferably consist essentially of one or more of thefollowing groupings of elements, oxides thereof, salts thereof, ormixtures of the same: (i) Ti, Ta, Nb, Hf, W, Y, Zn, Zr, Al, (ii) Ti, Ta,Nb, Hf, W and Y; (iii) Ti, Ta, Nb, Hf and W; (iv) Ti, Ta, Nb, Co and Zr(v) Ti, Ta, Nb and Co, (vi) Ti, Ta, Nb and Zr, and (vii) Ti, Ta and Nb.The minor component can likewise consist essentially of each of theaforementioned minor-component elements (Ti, Ta, Nb, Co Hf, W, Y, Zn, Zror Al) individually, oxides thereof, salts thereof, or mixtures of thesame. With respect to each of the aforementioned groupings of elementsor individual elements, the minor component(s) preferably consistessentially of oxides of one or more of the minor-component elements,but can, however, also include various amounts of such elements and/orother compounds (e.g., salts) containing such elements. An oxide of suchminor-component elements is an oxide thereof where the respectiveelement is in an oxidation state other than the fully-reduced state, andincludes oxides having an oxidation states corresponding to known stablevalence numbers, as well as to oxides in partially reduced oxidationstates. Salts of such minor-component elements can be any stable saltthereof, including, for example, nitrates, carbonates and acetates,among others. The amount of the oxide form of the particular recitedelements present in one or more of the minor component(s) is at leastabout 5%, preferably at least about 10%, preferably still at least about20%, more preferably at least about 35%, more preferably yet at leastabout 50% and most preferable at least about 60%, in each case by molesrelative to total moles of the particular minor component. Without beingbound by theory not specifically recited in the claims, the one or morefirst minor components provide a matrix environment for the Ni/Ni oxideactive metal center and help maintain the active metal center welldispersed. Although the first minor components can themselves be redoxinactive under reaction conditions, particularly to oxygen andhydrocarbons, they are nonetheless considered to be a component of thecatalytically active compound or composition. As noted below, the firstminor component can also have a support or carrier functionality.

In another, preferred embodiment, the nickel catalyst can comprise (i) amajor component consisting essentially of Ni oxide; and (ii) a minorcomponent consisting essentially of one or more of the following oxides,considered individually or collectively in the various permutations: Tioxide, Ta oxide, and/or Nb oxide, optionally together with one or moreof Hf oxide, W oxide, and/or Y oxide, optionally together with one ormore of Zn oxide, Zr oxide and/or Al oxide.

In addition to the aforementioned minor component(s) of the catalyst(generally referred to hereinafter as “first minor components”), thecatalyst can additionally comprise one or more second minor components.The second minor component(s) can consist essentially of an element orcompound selected from the group consisting of a lanthanide element, agroup IIIA element, a group VA element, a group VIA element, a groupIIIB element, a group IVB element, a group VB element, a group VIBelement, oxides thereof and salts thereof, or mixtures of such elementsor compounds. The second minor component preferably consists essentiallyof an element or compound selected from the group consisting of La, Ce,Pr, Nd, Sm, Sb, Sn, Bi, Pb, Tl, In, Te, Cr, V, Mn, Mo, Fe, Co, Cu, Ru,Rh, Pd, Pt, Ag, Cd, Os, Re, Ir, Au, Hg, oxides thereof and saltsthereof, or mixtures of such elements or compounds. More preferably, thesecond minor component consists essentially of an element or compoundselected from the group consisting of La, Ce, Pr, Nd, Sm, Sb, Sn, Bi,Co, Ag, Cr, oxides thereof and salts thereof, or mixtures of suchelements or compounds. If Co is considered within the group of firstminor components, it can be excluded from the aforementioned groups ofsecond minor components. The second minor component is preferably anoxide of one of the aforementioned second-minor-component elements. Theoxides and salts can be as described above in connection with thefirst-minor components. Without being bound by theory not specificallyrecited in the claims, the second minor component can be redox activecomponents with respect to enhancing the redox potential of the Ni/Nioxide active metal centers.

The catalyst can also include, as yet a further (third) minorcomponent(s), one or more of an element or compound selected from thegroup consisting of the alkali metals, the alkaline earth metals, oxidesthereof, and salts thereof, or mixtures of such elements or compounds.Preferably, the third minor component consists essentially of an elementor compound selected from the group consisting of Ca, K, Mg, Sr, Ba, Liand Na, most preferably Ca, K and Mg, and in either case, oxides thereofand salts thereof, or mixtures of such elements or compounds. The thirdminor component is preferably an oxide of one of the aforementionedthird-minor-component elements. The oxides and salts can be as describedabove in connection with the first-minor components. Without being boundby theory not specifically recited in the claims, the third minorcomponents are preferably basic metal oxides, and as such, can beemployed to optimize the acidity or basicity, in particular with respectto selectivity.

The catalyst can include other components as well, and can be part of acomposition that includes other components or agents (e.g., diluents,binders and/or fillers, as discussed below) as desired in connectionwith the reaction system of interest.

In a further embodiment, the nickel catalyst of the invention can be amaterial comprising a mixed-metal oxide compound having the formula (I):Ni_(x)A_(a)B_(b)C_(c)O_(d)  (I),where, A, B, C, x, a, b, c and d are described below, and can be groupedin any of the various combinations and permutations of preferences, someof which are specifically set forth herein.

In formula I, “x” represents a number ranging from about 0.1 to about0.96. The number x preferably ranges from about 0.3 to about 0.85, morepreferably from about 0.5 to about 0.9, and even more preferably fromabout 0.6 to about 0.8.

In formula I, “A” represents an element selected from the groupconsisting of Ti, Ta, Nb, Hf, W, Y, Zn, Zr and Al, or mixtures of two ormore thereof. A is preferably Ti, Ta, Nb, Hf, W or Y, even morepreferably Ti, Ta, Nb, Hf or W, and still more preferably Ti, Ta or Nb,or, in each case, mixtures thereof. The letter “a” represents a numberranging from about 0.04 to about 0.9, preferably from about 0.04 toabout 0.8, more preferably from about 0.04 to about 0.5, even morepreferably from about 0.1 to about 0.5, still more preferably from about0.15 to about 0.5 and most preferably from about 0.3 to about 0.4.

In formula I, “B” represents an element selected from the groupconsisting of a lanthanide element, a group IIIA element, element, agroup VA element, a group VIA element, a group VIIA element, a groupVIIIA element, a group IB element, a group IIB element, a group IIIBelement, a group IVB element, a group VB element, a group VIB element,and mixtures of two or more thereof. As used herein, periodic tablesubgroup designations are those recommended by the International Unionof Pure and Applied Chemistry (IUPAC), such as shown on the PeriodicTable of the Elements, Learning Laboratories, Inc. (1996). B ispreferably an element selected from the group consisting of La, Ce, Pr,Nd, Sm, Sb, Sn, Bi, Pb, Tl, In, Te, Cr, V, Mn, Mo, Fe, Co, Cu, Ru, Rh,Pd, Pt, Ag, Cd, Os, Re, Ir, Au, and Hg. B is more preferably an elementselected from the group consisting of La, Ce, Pr, Nd, Sm, Sb, Sn, Bi,Co, Cr and Ag. The letter “b” represents a number ranging from 0 toabout 0.5, more preferably from 0 to about 0.4, even more preferablyfrom 0 to about 0.2, still more preferably from 0 to about 0.1, and mostpreferably from 0 to about 0.05.

In formula I, C is an alkali metal, an alkaline earth metal or mixturesthereof. C is preferably an element selected from the group consistingof Ca, K, Mg, Li, Na, Sr, Ba, Cs and Rb, and is more preferably anelement selected from the group consisting of Ca, K and Mg. The letter“c” represents a number ranging from 0 to about 0.5, more preferablyfrom 0 to about 0.4, even more preferably from 0 to about 0.1, and mostpreferably from 0 to about 0.05.

In formula I, “O” represents oxygen, and “d” represents a number thatsatisfies valence requirements. In general, “d” is based on theoxidation states and the relative atomic fractions of the various metalatoms of the compound of formula I (e.g., calculated as one-half of thesum of the products of oxidation state and atomic fraction for each ofthe metal oxide components).

In one preferred mixed-metal oxide embodiment, where, with reference toformula I, “b” and “c” are each zero, the catalyst material can comprisea compound having the formula I-A:Ni_(x)A_(a)O_(d)  (I-A),where Ni is nickel, O is oxygen, and where “x”, “A”, “a” and “d” are asdefined above.

In another preferred mixed-metal oxide embodiment, with reference toformula I, the sum of (a+b+c) is preferably less than or not more thanabout 0.9, is preferably not more than about 0.7, and is even morepreferably not more than about 0.5, and moreover, this sum preferablyranges from about 0.04 to about 0.6, more preferably from about 0.1 toabout 0.5 and most preferably from about 0.1 to about 0.4.

In still another preferred mixed-metal oxide embodiment, with referenceto formula I, the sum of (a+b+c) is preferably less than or not morethan about 0.5, is preferably not more than about 0.4, and is even morepreferably not more than about 0.3, and moreover, this sum preferablyranges from about 0.04 to about 0.5, more preferably from about 0.1 toabout 0.4 and most preferably from about 0.1 to about 0.3.

In an additional preferred mixed-metal oxide embodiment, with referenceto formula I: A is Ti, Ta, Nb or Zr, or preferably, Ti, Ta or Nb; B isLa, Ce, Pr, Nd, Sm, Sb, Sn, Bi, Cr, Co or Ag, or preferably, La, Ce, Pr,Nd, Sm, Sb, Sn or Bi; and C is Ca, K or Mg. In this embodiment, x rangesfrom about 0.1 to about 0.96, and preferably from about 0.5 to about0.96, a ranges from about 0.3 to about 0.5, c ranges from about 0.01 toabout 0.09, and preferably from about 0.01 to about 0.05, and d is anumber that satisfies valence requirements.

In a further preferred mixed-metal oxide embodiment, with reference toformula I, A is Ti and Ta in combination, Ti and Nb in combination, orTa and Nb in combination, B is La, Ce, Pr, Nd, Sm, Sb, Sn, Bi, Co, Crand Ag, and C is Ca, K or Mg. In this embodiment, x ranges from about0.1 to about 0.96, and preferably from about 0.5 to about 0.96, a rangesfrom about 0.3 to about 0.5, c ranges from about 0.01 to about 0.09, andpreferably from about 0.01 to about 0.05, and d is a number thatsatisfies valence requirements.

In a particularly preferred mixed-metal oxide embodiment, with referenceto formula I, A is Ti, B is Sb, Sn, Bi, Co, Ag or Ce and C is Sr, Ca, Mgor Li. In this embodiment, x ranges from about 0.5 to about 0.9, aranges from about 0.15 to about 0.4, c ranges from 0 to about 0.05, andd is a number that satisfies valence requirements.

In another particularly preferred mixed-metal oxide embodiment, withreference to formula I, A is Ta, B is Sb, Sn, Bi, Co, Ag or Ce and C isSr, Ca, Mg or Li. In this embodiment, x ranges from about 0.5 to about0.9, a ranges from about 0.15 to about 0.4, c ranges from 0 to about0.05, and d is a number that satisfies valence requirements.

In a further particularly preferred mixed-metal oxide embodiment, withreference to formula I, A is Nb, B is Sb, Sn, Bi, Co, Ag or Ce and C isSr, Ca, Mg or Li. In this embodiment, x ranges from about 0.5 to about0.9, a ranges from about 0.15 to about 0.4, c ranges from 0 to about0.05, and d is a number that satisfies valence requirements.

In still a further preferred embodiment, the nickel catalyst of theinvention can be a material comprising a mixed-metal oxide compoundhaving the formula II:Ni_(x)Ti_(j)Ta_(k)Nb_(l)La*Sb_(r)Sn_(s)Bi_(t)Ca_(u)K_(v)Mg_(w)O_(d)  (II),where “x” and “d” are as described above, and La*, j, k, l, r, s, t, u,v and w are described below, together with preferred relationshipsbetween respective elements. The various recited elements of formula IIcan be grouped in any of the various combinations and permutations ofpreferences, some of which are specifically set forth herein.

In formula II, each of “j”, “k” and “l” represent a number ranging from0 to about 0.8, preferably from 0 to about 0.5, and more preferably from0 to about 0.4. The sum of (j+k+1) is at least about 0.04, preferably atleast about 0.1 5, and more preferably at least about 0.3.

In formula II, La* refers to one or more lanthanide series elementsselected from the group consisting of La_(m), Ce_(n), Pr_(o), Nd_(p),Sm_(q), and preferably. Each of “m”, “n”, “o”, “p”, “q”, “r”, “s” and“t” refer to numbers ranging from 0 to about 0.2, preferably from zeroto about 0.1, and more preferably from zero to about 0.05. The sum of(m+n+o+p+q+r+s+t) is preferably at least about 0.005, more preferably atleast about 0.01, and can, in some embodiments, be at least about 0.05.

In formula II, each of “u”, “v” and “w” refer to numbers ranging from 0to about 0.4, preferably from 0 to about 0.1 and more preferably from 0to about 0.05.

The nickel catalyst of the invention is preferably a supported catalyst.The catalyst can therefore further comprise, in addition to one or moreof the aforementioned compounds or compositions, a solid support orcarrier. The support is preferably a porous support, with a pore sizetypically ranging, without limitation, from about 2 nm to about 100 nmand with a surface area typically ranging, without limitation, fromabout 5 m²/g to about 300 m²/g. The particular support or carriermaterial is not narrowly critical, and can include, for example, amaterial selected from the group consisting of silica, alumina, zeolite,activated carbon, titania, zirconia, magnesia, zeolites and clays, amongothers, or mixtures thereof. Preferred support materials includetitania, zirconia, alumina or silica. In some cases, where the supportmaterial itself is the same as one of the preferred components (e.g.,Al₂O₃ for Al as a minor component), the support material itself mayeffectively form a part of the catalytically active material. In othercases, the support can be entirely inert to the dehydrogenation reactionof interest. Titania is a particularly preferred support, and can beobtained, for example, from commercial vendors such as Norton, Degussaor Engelhardt.

General approaches for preparing the nickel catalysts of the presentinvention—as supported or unsupported catalysts—are well known in theart. Exemplary approaches include, for example, sol-gel, freeze drying,spray drying, precipitation, impregnation, incipient wetness, sprayimpregnation, ion exchange, wet mix/evaporation, dry mix/compacting,high coating, fluid bed coating, bead coating, spin coating, physicalvapor deposition (sputtering, electron beam evaporation, laser ablation)and chemical vapor deposition, among others. The particular technical ornon-technical technique employed is not narrowly critical. Preferredapproaches, include, for example, impregnation techniques, precipitationtechniques, sol-gel, evaporation, incipient wetness and spray drying,among others. The catalyst may take any suitable forms (e.g., granular,tablets, etc.), as discussed in greater detail below.

According to one exemplary approach for preparing a supportedmixed-metal oxide catalyst of the invention, a composition comprisingeach of the desired elements of the active oxide components of thecatalyst (i.e., the major component and one or more minor components)can be formed, and then optionally calcined to form the correspondingmixed-metal oxide. The pre-calcination composition can be formed, in thefirst instance for example, in a liquid state as a solution, dispersion,slurry or sol, by combining the major component, the first minorcomponent(s), and optionally, the second and/or third minorcomponent(s). The pre-calcination composition can then be formed as asolid having the same relative ratios of the various components, forexample, by being impregnated into, situated on, or formed in-situ withthe support or carrier (e.g., via precipitation or sol-gel approaches).For example, a pre-calcination composition formed as a solution ordispersion can be impregnated into or onto the support, and then dried.Alternatively, pre-calcination solution or dispersion can beprecipitated, recovered and then dried. A pre-calcination sol can becured (gelled) to form the corresponding solid composition. In any case,pre-calcination compositions can be otherwise treated (e.g., heated) asdesired (e.g., to drive off solvents).

Preferred pre-calcination compositions of the invention can comprise, oralternatively consist essentially of, a compound represented by FormulaI-B:Ni_(x)A_(a)B_(b)C_(c)  (I-B),or salts thereof, where “x”, “A”, “B”, “C”, “a”, “b” and “c” are each asdefined above in connection with the preferred mixed-oxide catalyst. Aparticularly preferred pre-calcination composition can comprise, oralternatively consist essentially of, a compound represented by FormulaII-B:Ni_(x)Ti_(j)Ta_(k)Nb_(l)La*Sb_(r)Sn_(s)Bi_(t)Ca_(u)K_(v)Mg_(w)  (II-B),or salts thereof, where “x”, “j”, “k”, “La*”, “r”, “s”, “t”, “u”, “v”and “w” are each as defined above in connection with the preferredmixed-oxide catalyst. The preferred pre-calcination compositions can bein a liquid state (e.g., solution, dispersion, slurry or sol) or a solidstate.

According to one method for forming the preferred pre-calcinationcomposition, salts of the various elements are combined to form asolution or liquid dispersion thereof, (“precursor solutions”). Themetal salt precursor solutions are preferably aqueous solutions, and cantypically include metal cations with counterions selected from nitrates,acetates, oxalates, and halides, among others. The metal salt precursorsolutions can also be organic solutions or sol-gels comprising suchmetal cations and counterions, as well as other counterions (e.g.,alkoxides). When halides are used as a counterion, the resultingcatalyst is preferably subsequently rinsed extensively (e.g., withwater) to remove halide. Particularly preferred salts for Ni, Ti, Nb, Taand Zr include, for example, nickel nitrate, titanium oxalate, niobiumoxalate, tantalum oxalate, and zirconium oxalate. The mixed-metal saltsolutions can then be impregnated into a support, preferably a titaniasupport. The volume of mixed-metal salt solutions used for impregnatingthe catalyst will depend on the pore volume of the support, and cantypically range from about 0.1 to about 2, preferably from about 0.1 toabout 1 times the pore volume thereof. The pH is preferably maintainedat about 2 to about 6. The catalyst-impregnated support can then bedried, preferably at reduced pressure (ie., under vacuum), at atemperature ranging from about 20° C. to about 100° C. for a period oftime ranging from about 5 minutes to about 2 hours to form a semi-solidor solid pre-calcination composition.

According to an alternative approach, various aqueous solutionscomprised of water-soluble metal precursors can be combined in propervolumetric ratios to obtain combined solutions (or mixtures) havingdesired metal compositions. Water can be separated from the metal-saltcomponents of the combined solutions (or mixtures) by lyophilization,precipitation and/or evaporation. Lyophilization refers to freezing theresulting mixture (e.g., under liquid nitrogen), and then placing themixture in a high vacuum so that the water (ice) sublimes, leavingbehind mixtures of dry metal precursors. Precipitation refers toseparating dissolved metal ions by adding one or more chemical reagentsthat will precipitate sparingly soluble salts of the metal ions. Suchchemical reagents may provide ions that shift ionic equilibrium to favorformation of insoluble metal salts (common ion effect), or may bind withmetal ions to form uncharged, insoluble coordination compounds(complexation). In addition, such reagents may oxidize or reduce metalions to form ionic species that produce insoluble salts. Otherprecipitation mechanisms include hydrolysis, in which metal ions reactwith water in the presence of a weak base to form insoluble metal salts,or the addition of agents (e.g., alcohols) that affect the polarity ofthe solvent. Regardless of the particular mechanism, the precipitate canbe separated from the remaining solution by first centrifuging thesolutions and then decanting the supernatant; residual water can beremoved by evaporation of water from the precipitates to form asemi-solid or solid pre-calcination composition. Evaporation refers toremoving water by heating and/or under vacuum to form a semi-sold orsolid pre-calcination composition.

The solid pre-calcination composition can be calcined according tomethods known in the art. Calcination conditions can affect the activityof the catalyst, and can be optimized by a person of skill in the art,particularly in connection with a particular catalyst composition and/ordehydrogenation reaction conditions. Calcination is, without limitation,preferably effected at temperatures ranging from about 250° C. to about600° C., and more preferably from about 275° C. to about 400° C. Thecalcination is preferably effected for period of time, and at atemperature sufficient to provide the desired metal oxide catalystcomposition. Typically, calcination is effected for a total, cumulativeperiod of time of at least about 0.1 hour, and typically at least about1 hour, with actual calcination times depending on temperature accordingto approaches known in the art. The calcination environment ispreferably an oxidizing environment (e.g., comprising air or othersource of molecular oxygen), but can also be an inert environment. Inthe case of inert calcination, oxidation of the metal components of thecatalyst can be effected in situ during the reaction, by oxidizing underreaction conditions. Hence, calcination can be effected prior to loadingthe catalyst into a reaction zone, or alternatively, can be effected insitu in the reaction zone prior to the reaction.

Finally, regardless of the particular approach used to form thecatalyst, the solid pre-calcination composition or the calcinationproduct (catalyst) can be ground, pelletized, pressed and/or sieved toensure a consistent bulk density among samples and/or to ensure aconsistent pressure drop across a catalyst bed in a reactor. Furtherprocessing can also occur, as discussed below.

The active catalyst of the invention can be included in a catalystcomposition comprising other, inactive components. The catalyst may, forexample, be diluted (e.g., have its concentration reduced) with bindersand/or inert fillers, which are known to those of skill in the art,including for example quartz chips, sand or cement. Diluents may beadded to the catalyst in the range of from about 0 to about 30% byvolume, preferably in the range of from about 10 to about 25% by volume.Preferred diluents can improve the heat removal or heat transfer of thecatalyst to help avoid hot spots or to modify hot spots. Bindersgenerally provide mechanical strength to the catalyst and may be addedin the range of from about 0–30% by volume, preferably in the range offrom about 5 to about 25% by volume. Useful binders include silica sol,silica, alumina, diamataceous earth, hydrated zirconia, silica aluminas,alumina phosphates, naturally occurring materials and cement andcombinations thereof. See, e.g., the discussion of supports, shapes,binders and fillers in U.S. Pat. Nos. 5,376,613, 5,780,700 and4,250,346, each of which is incorporated herein by reference for allpurposes. The percentages or amounts of binders, fillers or organicsreferred to herein relate to the starting ingredients prior tocalcination. Thus, the above is not intended to imply statements on theactual bonding ratios, to which the invention is not restricted; forexample during calcination other phases may form.

The catalyst or catalyst composition is provided to a reaction zone of areactor. The reactor is preferably a fixed-bed flow reactor, but othersuitable reactor designs—including batch reactors and flow reactors(e.g., fluidized bed reactors)—can also be employed. The catalyst ispreferably provided in the reaction zone (e.g., in a fixed-bed) as asupported catalyst, but may also be provided as an unsupported catalyst(e.g., bulk, pelletized catalyst). The catalyst may take any form,including powder, split, granular, pellets or a shaped catalyst, such astablets, rings, cylinders, stars, ripped bodies, extrudates, etc., eachof which are known to those of skill in the art. For example, theshaping of the mixture of starting composition may be carried out bycompaction (for example tableting or extrusion) with or without a priorkneading step, if necessary with addition of conventional auxiliaries(e.g., graphite or stearic acid or its salts as lubricants). In the caseof unsupported catalysts, the compaction gives the desired catalystgeometry directly. Hollow cylinders may have an external diameter andlength of from 2 to 10 mm and a wall thickness of from 1 to 3 mm.Generally, the mixture of starting composition metal may be shapedeither before or after the calcination. This can be carried out, forexample, by comminuting or grinding the mixture before or aftercalcination and applying it to inert supports to produce coatedcatalysts.

As discussed in greater detail below, co-catalysts can also be providedto the reaction zone, together with the catalyst of the presentinvention (in separate phases or as an integrated catalyst composition).

An alkane or other reactant to be dehydrogenated is provided to thereaction zone of the reactor containing the catalyst. Typically andpreferably, the dehydrogenation substrate reactant is provided to thereaction zone as a gas or in a gaseous state. Liquid reactants can bevaporized by methods and devices known in the art and entrained in amoving stream of gaseous fluid.

The alkane can be substituted or unsubstituted. The alkane is preferablyan alkane having from 2 to 6 carbon atoms (a “C₂ to C₆ alkane”) or asubstituted C₂ to C₆ alkane, and preferably an alkane having from 2 to 4carbon atoms (a “C₂ to C₄ alkane”) or a substituted C₂ to C₄ alkane.Preferred C₂ to C₆ alkane reactants include ethane, propane,isopropanol, n-butane, isobutane, and isopentane, with ethane beingparticularly preferred. The oxidative dehydrogenation reaction forconversion of ethane to ethylene is representative:C₂H₆+½O₂→C₂H₄+H₂OThe corresponding alkenes for other preferred C₂ to C₄ alkanes includepropylene (from propane), acetone (from isopropanol), 1-butene and/or2-butene (from n-butane), isobutene (from isobutane), isoamylenes (fromisopentane), and isoprene. Preferred substituted C₂ to C₄ alkanesinclude halide-substituted C₂ to C₄. For example, ethyl chloride can beoxidatively dehydrogenated using the catalysts and methods describedherein to form the vinyl chloride.

Although the present invention is described and exemplified primarily inconnection with dehydrogenation of the aforementioned alkanes,dehydrogenation of other alkanes using the catalysts and methodsdisclosed herein is also contemplated, and is within the scope of theinvention. For example, cyclohexane can be oxidatively dehydrogenatedover the nickel catalysts of the invention to form benzene. Moreover,the nickel catalysts of the invention can also be used fordehydrogenating other hydrocarbon substrates, such as alkenes, to one ormore dehydrogenation product(s). The dehydrogenation of butene to form abutadiene, and the dehydrogenation of isoamylenes to form isoprene areexemplary.

An oxidant is also provided to the reaction zone of the reactorcontaining the catalyst. The oxidant is preferably a gaseous oxidant,but can also include a liquid oxidant or a solid-state oxidant. Thegaseous oxidant is preferably molecular oxygen, and can be provided asoxygen gas or as an oxygen-containing gas. The oxygen containing gas canbe air, or oxygen or air that has been diluted with one or more inertgases such as nitrogen. Other gaseous oxidants, such as N₂O or NO, canalso be used in the oxidative dehydrogenation reaction. In cases inwhich the alkane is oxidatively dehydrogenated in the substantialabsence of a gaseous oxidant during the reaction (e.g., using a solidoxidant), the oxidant may be periodically regenerated—either byperiodically withdrawing the catalyst from the reaction zone or byregenerating the catalyst in situ in the reaction zone (during orin-between reaction runs).

The sequence of providing the catalyst, reactant and oxidant to thereaction zone is not critical. Typically, the catalyst is provided inadvance (or as noted above, even formed in situ in the reaction vesselfrom a pre-calcination composition), and the alkane gas and oxidant gasare provided subsequently—either together as a mixed gas through acommon feed line, or alternatively, separately, but simultaneously,through different feed lines. In general, the simultaneous supply ofalkane and gaseous oxidant to the reaction zone is referred to as“co-feed” regardless of the particular feed configuration employed.

The amount of catalyst loaded to the reaction zone of the reactor,together with the relative amounts of alkane (or other reactant) andoxidant provided to the reaction zone, can vary, and are preferablycontrolled—together with reaction conditions, as discussed below—toeffect the dehydrogenation reaction with favorable and industriallyattractive performance characteristics. In general, the catalyst loadingto the reaction zone will vary depending on the type of reactor, thesize of the reaction zone, the form of the catalyst, required contacttimes, and/or the desired amount or flow-rates of reactants and/orproducts. The absolute amount of alkane or other reactant and oxidantcan likewise vary, depending primarily on the aforementioned factors,and can be optimized by persons of skill in the art to achieve the bestperformance. In general, lower oxidant concentration tends to limit theextent of over-oxidation, and therefore, favor higher alkeneselectivity. Such lower oxidant concentrations, however, can alsoadversely affect the alkane conversion. For conversion of ethane toethylene using molecular oxygen, for example, the molar ratio of ethaneto molecular oxygen, C₂H₆:O₂, in the reaction zone (or being fed to thereaction zone) can range from about 1:1 to about 40:1, preferably fromabout 2:1 to about 40:1, more preferably from about 66:34 to about 20:1,and most preferably from about 5:1 to about 20:1. In some particularlypreferred embodiments—such as where multi-stage reactors are employed,as discussed below—the C₂H₆:O₂ ratio can preferably range from about 5:1to about 40:1, and preferably from about 5:1 to about 15:1, oralternatively, from about 10:1 to about 20:1. For the conversion ofgaseous alkanes such as ethane with molecular oxygen, for example, therelative amounts of reactant and oxidant can alternatively be expressedin terms of volume percentages in reactor feed (for mixed-feed co-feedconfiguration) or in the reaction zone (regardless of co-feedconfiguration), with molecular oxygen preferably ranging from about0.01% to about 34% by volume and the alkane preferably ranging fromabout 66% to about 99% by volume. The amount of molecular oxygen morepreferably ranges from about 0.01% to about 20% by volume, and theamount of alkane more preferably ranges from about 80% to about 99% byvolume. Flammability limits should be observed for safety reasons.

Other materials may also be provided to the reaction zone. For example,the reactor feed can also include diluents such as nitrogen, argon orcarbon dioxide. For some reactions, and/or for some embodiments,discussed in greater detail below, the reactor feed may comprise watervapor, or amounts of various reaction products (e.g., alkenes such asethylene, propylene or butenes).

The alkane and the gaseous oxidant contact the catalyst in a reactionzone of a reactor under controlled reaction conditions, and the alkaneis dehydrogenated to form the corresponding alkene(s). Without beingbound by theory, the alkane contacts the catalyst in the presence of theoxidant and is dehydrogenated; the hydrogen atoms combine with an oxygenfrom the oxidant to form the corresponding alkene(s) and water asreaction products. Contact between the reactant substrate, gaseousoxidant and catalyst can occur, for example, as a mixture of the feedgasses passes through or around the interstices of the fixed-bedcatalyst and/or over an exposed surface of the catalyst. The contacttime (or residence time) can vary, and can be optimized by persons ofskill in the art. Generally, and without limitation, contact times canrange from about 0.1 seconds to about 10 seconds, and preferably fromabout 0.5 seconds to about 5 seconds. Without limitation, the gas spacevelocity SV in the vapor phase reaction can range from about 100/hr toabout 10,000/hr, preferably from about 300/hr to about 6,000/hr, andmore preferably from about 300/hr to about 2,000/hr. Inert gas(es) canbe used, if desired, as a diluting gas to adjust the space velocity. Thetemperature and pressure of the reaction zone can likewise vary, and canlikewise be optimized by persons of skill in the art. Withoutlimitation, the temperature preferably ranges from about 200° C. toabout 500° C., more preferably from about 200° C. to about 400° C., evenmore preferably from about 250° C. to about 400° C., still morepreferably from about 250° C. to about 350° C., and yet more preferablyfrom about 275° C. to about 325° C., and most preferably from about 275°C. to about 300° C. In one embodiment of the invention, the temperatureof the reaction zone during the dehydrogenation reaction is preferablycontrolled to be less than about 300° C. Alkane oxidativedehydrogenation is an exothermic reaction, and adequate heat transfer(cooling) can be achieved using methods known in the art, including forexample, cooling with steam. Without limitation, the reaction pressurecan range from atmospheric pressure to about 20 bar, and preferablyranges from about 1 bar to about 10 bar.

The relative alkane and oxidant feeds, catalyst loading, and reactionconditions are preferably controlled, individually and collectivelyamong the various possible permutations, to achieve a reactionperformance that is suitable for industrial applications. Morespecifically, the alkane and oxidant feeds, catalyst loading andreaction conditions are controlled such that the alkane isdehydrogenated to its corresponding alkene(s) with an alkane conversionof at least about 5%, preferably at least about 10%, and an alkeneselectivity of at least about 70%, and preferably at least about 75%.Using the catalysts and process disclosed herein, the aforementionedreaction parameters can be controlled to achieve a conversion of atleast about or greater than 15%, and more preferably at least about 20%or higher, and to achieve a selectivity for the alkene of at least aboutor greater than about 80%, preferably at least about or greater thanabout 85%, and most preferably at least about or greater than about 90%.Within experimental error, selectivity is substantially independent ofconversion.

As used herein, “conversion” refers to the percentage of the amount ofalkane provided to the reaction zone that is converted to carbonproducts, and can be expressed as follows:

${\%\mspace{14mu}{conversion}} = {100 \times \frac{\begin{matrix}{{The}\mspace{14mu}{molar}\mspace{14mu}{alkane}\text{-}{equivalent}\mspace{14mu}{sum}\mspace{14mu}\left( {carbon} \right.} \\{{\left. {basis} \right)\mspace{14mu}{of}\mspace{14mu}{all}\mspace{14mu}{carbon}\text{-}{containing}\mspace{14mu}{products}},} \\{{excluding}\mspace{14mu}{the}\mspace{14mu}{alkane}\mspace{14mu}{in}\mspace{14mu}{the}\mspace{14mu}{{effluent}.}}\end{matrix}}{\begin{matrix}{{Moles}\mspace{14mu}{of}\mspace{14mu}{alkane}\mspace{14mu}{in}\mspace{14mu}{the}\mspace{14mu}{reaction}} \\{{mixture}\mspace{14mu}{which}\mspace{14mu}{is}\mspace{14mu}{fed}\mspace{14mu}{to}\mspace{14mu}{the}\mspace{14mu}{catalyst}} \\{{in}\mspace{14mu}{the}\mspace{14mu}{reactor}}\end{matrix}}}$As used herein, “selectivity” (also known as efficiency), orequivalently, “alkene selectivity” refers to the percentage of theamount of converted alkane (i.e., total carbon products) that isconverted to the specifically desired alkene product, and can beexpressed as follows:

${\%\mspace{14mu}{selectivity}} = {100 \times \frac{{Moles}\mspace{14mu}{of}\mspace{14mu}{desired}\mspace{14mu}{alkene}\mspace{14mu}{produced}}{\begin{matrix}{{The}\mspace{14mu}{molar}\mspace{14mu}{alkene}\text{-}{equivalent}\mspace{14mu}{sum}\mspace{14mu}\left( {carbon} \right.} \\{{\left. {basis} \right)\mspace{14mu}{of}\mspace{14mu}{all}\mspace{14mu}{carbon}\text{-}{containing}\mspace{14mu}{products}},} \\{{excluding}\mspace{14mu}{the}\mspace{14mu}{alkane}\mspace{14mu}{in}\mspace{14mu}{the}\mspace{14mu}{{effluent}.}}\end{matrix}}}$These expressions are the theoretical expressions for selectivity andconversion. Simplified formulas have been used in the examples herein,and may be Used by those of skill in the art for alkaneoxydehydrogenation reactions where CO₂ is the primary side product—forexample, where the only products observed in the ethane oxidativedehydrogenation (using an ethane and molecular oxygen gas feed) areethylene and carbon dioxide. In such cases, the simplified formula for %conversion is % conversion=100×[(moles of alkene+((moles of carbondioxide)/2))/(moles of alkane)]. The simplified formula for %selectivity is % selectivity=100×[(moles of alkene)/(moles ofalkene+((moles of carbon dioxide)/2))]. When the alkane is ethane orpropane, only one dehydrogenation product is possible, and thecalculations are straightforward. When butane is the alkane, however,the dehydrogenation product can be one or more of 1-butene, 2-butene or1,3-butadiene. Thus, for butane dehydrogenation reactions, thepercentages for selectivity and conversion may be based on one or moreof these butane dehydrogenation products.

The nickel oxide/mixed-metal oxide catalysts of the present inventionoffer significant performance advantages as compared to currentindustrially-important (V-Mo) catalysts. For example, the catalysts ofthe invention can result in about a 20% conversion with about a 90%selectivity, as compared to about a 5% conversion with a 90% selectivityof the current industrially-important alternative. Moreover, thespace-time yield achieved based on bulk-scale testing of the inventioncatalysts in laboratory-scale equipment is about 300 kg ethyleneproduced per m³ of catalyst per hour—an improvement of a factor of aboutten (10) as compared to known MoV-based catalysts.

The nickel oxide/mixed-metal oxide catalysts of the present inventionare stable with respect to dehydrogenation activity and performancecharacteristics. Stability of the catalyst is demonstrated by lifetimetesting, in which a C₂ to C₄ alkane or a substituted C₂ to C₄ alkane anda gaseous oxidant are co-fed to a reaction zone containing the catalystwhile maintaining the reaction zone (and the catalyst) at temperatureranging from about 200° C. to about 500° C., preferably from about 250°C. to about 350° C., and more preferably from about 250° C. to about300° C. The alkane is contacted with the catalyst in the presence of thegaseous oxidant to dehydrogenate the alkane and to form thecorresponding alkene. The alkene, unreacted alkane and unreacted gaseousoxidant are exhausted or otherwise removed from the reaction zone. Thesteps of co-feeding the reactants, dehydrogenating the alkane, andexhausting the alkene and unreacted reactants are effected for acumulative reaction period of not less than about 200 hours, preferablynot less than about 400 hours, more preferably not less than about 600hours, even more preferably not less than about 1000 hours, and mostpreferably not less than about 2000 hours. In commercialindustrial-scale applications, the catalyst is preferably stable for atleast about 5000 hours, and more preferably at least about 8000 hours.

Significantly, the nickel-containing mixed-metal oxide catalyst of thepresent invention has activity for selectively converting alkane to thecorresponding alkene/olefin (e.g., ethane to ethylene) even in thepresence of substantial amounts of alkene/olefin (e.g., ethylene) in thereaction zone. Specifically, the alkane can be oxidativelydehydrogenated to form the corresponding alkene in the reactionzone—even when the reaction zone comprises the corresponding alkene in amolar concentration of at least about 5%, relative to total moles ofhydrocarbon, during the oxydehydrogenation—with an alkane conversion ofat least about 5% and an alkene selectivity of at least about 50%. Aconversion of at least about 5% and a selectivity of at least about 50%can likewise be achieved where the molar concentration of thecorresponding alkene in the reaction zone ranges from about 5% to about50%, or where the molar concentration thereof is at least about 10%, atleast about 20%, at least about 30%, at least about 40% or at leastabout 50%, relative to total moles of hydrocarbon. Moreover, alkaneconversions as high as 10% with alkene selectivity as high as 70% can beachieved where the molar concentration the corresponding alkene in thereaction zone is at least about 30% relative to total moles ofhydrocarbon. The relatively low product-sensitivity of the catalystactivity is surprising, particularly with respect to ethane conversion,because ethylene is typically more reactive than ethane over mostcatalysts.

The lack of product-inhibition on catalyst activity can beadvantageously employed in a number of ways. First, for example, aless-pure, mixed feed comprising both alkane and the correspondingalkene can be selectively enriched in the alkene. For example, a 70%ethane/30% ethylene feed stream, by volume, can be enriched byconversion to a 60% ethane/40% ethylene product stream, by volume, orfurther, to a 50% ethane/50% ethylene product stream, by volume. As amore specific example, raffinate II (a mixture of butane, 2-butenes and1-butene gasses) can be selectively enriched in the butenes at theexpense of butane, ultimately resulting in a more uniform streamcomposition. Such enrichment schemes may be particularly important ifemployed in connection with separation schemes that are more effectivewith streams having higher alkene content.

As another embodiment, exemplary of the advantageous catalytic activityof the catalyst, a single-stage reactor system can be configured torecycle the product stream (or a portion thereof) back to the feedstream, resulting in an overall improvement in conversion andselectivity. More specifically, with reference to FIG. 1A, the alkane(e.g., C₂H₆) and gaseous oxidant (e.g., O₂) are co-fed through feedconduits 5 to a reaction zone 10 containing the catalyst 100, the alkaneis dehydrogenated in the reaction zone 10 to form the correspondingalkene, the resulting product stream 15 (comprising the correspondingalkene, unreacted alkane and optionally any excess gaseous oxidant) isexhausted from the reaction zone 10, and a portion or all of the alkene-and unreacted-alkane-containing product stream 15 is then recycled backto the reaction zone via recycle line 25 (and is typically recombinedwith a fresh feed stream 5). As a variation of the basic recyclingembodiment discussed in the immediately-preceding paragraph, the productstream can be partially separated after being exhausted and before beingrecycled.

In a further, and generally preferred embodiment exemplifying theaforementioned advantage, a multi-stage reaction system can be effected,in which the product stream from a first reaction zone, or a portionthereof, becomes the feed stream for a second reaction zone. Morespecifically, with reference to FIG. 1B, an alkane (e.g., C₂H₆) and agaseous oxidant (e.g., O₂) can be co-fed through feed conduits 5 to afirst reaction zone 10, in which the alkane is dehydrogenated to formthe corresponding alkene, and the first product stream 15 comprising thecorresponding alkene and unreacted alkane from the first reaction zone10 is exhausted therefrom. The alkene- and unreacted-alkane-containingproduct stream 15 from the first reaction zone is then fed to a secondreaction zone 20—preferably with a co-feed of fresh gaseous oxidant viafeed conduit 5′ to the second reaction zone 20. The alkane is furtherdehydrogenated in the second reaction zone 20 to form the correspondingalkene therein. The alkene product is exhausted from the second reactionzone 20 as a product stream 15′. Additional stages of reaction zones (inone or more reactors) can likewise be added. The second (or furtheradditional) reaction zone(s) preferably comprises the alkene at a molarconcentration of at least about 5% relative to total moles hydrocarbon,and can be higher up to about 50%, as well as at one or more of theintermediate levels as described above. Significantly, because freshgaseous oxidant (e.g., molecular oxygen) can be added between each stageof the multi-stage reactor, the amount of gaseous oxidant can becontrolled at each stage to achieve an optimized selectivity andconversion for the dehydrogenation reaction occurring in that stage.This is particularly advantageous because low oxidant concentrations inthe feed typically favor more selective oxydehydrogenation reactions,with less formation of side-product (e.g., carbon dioxide). In preferredembodiments for ethane dehydrogenation to ethylene, the molarconcentration of oxygen in the first and second reaction zones iscontrolled to range from about 3% to about 40%, preferably from about 3%to about 20%, more preferably from about 5% to about 20%, and mostpreferably from about 8% to about 15%, in each case relative to ethane.The overall conversion and selectivity for ethane dehydrogenation toethylene with a multi-stage, multi-low-level oxygen co-feed system asdescribed herein is preferably at least about 5% alkane conversion andat least about 70% alkene selectivity, preferably at least about 80%alkene selectivity, preferably at least about 85% alkene selectivity,and more preferably at least about 90% alkene selectivity, and inanother embodiment, preferably at least about 10% alkane conversion andat least about 80% alkene selectivity, preferably at least about 85%alkene selectivity, and more preferably at least about 90% alkeneselectivity. In particularly preferred embodiments, the overallconversion is at least about 30%, more preferably at least about a valueranging from about 30% to about 45%, and the overall selectivity is atleast about 70%, more preferably at least about a value ranging fromabout 70% to about 85%.

Regardless of the particular reactor-configuration (e.g., single-stage,single-stage with recycle, multi-stage, multi-stage with multi-oxidantfeed, etc.), the resulting product stream typically comprises theproduct alkene/olefin of interest, together with unreacted alkane,possibly unreacted gaseous oxidant, as well as any side-product (e.g.,CO₂). The desired alkene product can be separated from the reactionproduct stream by methods known in the art. Preferably, for example, thealkene product can be recovered from the reaction product stream bycryogenic separation, by pressure-swing adsorption (e.g., on zeolites),by selective absorption. Additionally, or alternatively, the reactionproduct stream can be used, without further separation or with partialseparation (e.g., with removal of CO₂) as a feedstream to a downstreamreactor, where the alkene product can be reacted further (e.g., asdiscussed below).

The oxydehydrogenation products of the reactions disclosed herein (e.g.,ethylene, propylene, butenes, pentenes) can be further reacted to form anumber of commercially important downstream products.

Ethylene produced by the oxydehydrogenation of ethane using the nickeloxide/mixed-metal oxide catalyst of the present invention can, forexample, be further reacted to form polyethylene, styrene, ethanol,acetaldehyde, acetic acid, vinyl chloride, ethylene oxide, ethyleneglycol, ethylene carbonate, ethyl acetate and vinyl acetate, amongothers. More specifically, ethylene can be formed by oxidativelydehydrogenating ethane in the presence of a catalyst comprising (i) Ni,a Ni oxide, a Ni salt or mixtures thereof, and (ii) elements orcompounds selected from the group consisting of Ti, Ta, Nb, Hf, W, Y,Zn, Zr, Al, oxides thereof, and salts thereof, or mixtures of suchelements or compounds. The catalyst can be more specificallycharacterized as described above. The ethylene can be optionallypurified, and then further reacted to form a downstream reaction productof ethylene according to one or more of the following schemes.

Polyethylene. Ethylene can be polymerized to form polyethylene accordingto methods known in the art using a catalyst having activity forpolymerizing ethylene to polyethylene. Exemplary polymerizationapproaches include free-radical polymerization, and polymerization overZiegler (i.e., metal alkyl) catalysts. Styrene. Ethylene can be reactedwith benzene in the presence of acid catalysts such as aluminum chlorideor zeolites to form ethylbenzene, which can be catalyticallydehydrogenated (using a catalyst of the invention or knowndehydrogenation catalysts) to form styrene. Styrene can also be formeddirectly from the reaction of ethylene with benzene. Ethanol. Ethylenecan be hydrated to form ethanol according to methods known in the artusing a catalyst comprising an element or compound having activity forhydrating ethylene to ethanol. Preferred ethylene hydration catalystsinclude oxides of B, Ga, Al, Sn, Sb or Zn, or mixtures of such oxides.Water is preferably cofed to the reaction zone during the hydrationreaction. Acetaldehyde. Acetaldehyde can be formed from ethyleneaccording to methods known in the art—either directly, or through anethanol intermediate. In a direct route, ethylene is oxidized toacetaldehyde using a catalyst comprising an element or compound havingactivity for oxidizing ethylene to acetaldehyde. Preferred ethyleneoxidation catalysts for acetaldehyde formation include oxides of Pd, Cu,V or Co, or mixtures of such oxides. In an alternative, indirect route,ethylene is hydrated to form ethanol (as described above) and ethanol isthen oxidized to form acetaldehyde in the presence of a catalyst havingactivity for oxidizing ethanol to acetaldehyde. Preferred ethanoloxidation catalysts for acetaldehyde formation include metals and/ormetal oxides of Cu, Co, Ag, Re, Ru, Pt, Bi, Ce, Sb, In, Pd, Rh, Ir, V,Cr or Mn, or mixtures of such oxides. Acetic Acid. Ethylene can beoxidized to form acetic acid according to methods known in the art usinga catalyst comprising an element or compound having activity foroxidizing ethylene to acetic acid. The catalyst preferably comprises anoble metal or an oxide thereof, and more preferably, Pd or Pt or oxidesthereof. Water is preferably co-fed to the reaction zone during theethylene oxidation reaction. Vinyl Chloride. Ethylene can be chlorinatedor oxychlorinated to form vinyl chloride according to methods known inthe art. In a chlorination reaction, chlorine or other chlorinatingagent are preferably co-fed to the reaction zone, and ethylene ischlorinated in the presence of a catalyst having activity forchlorinating ethylene to vinyl chloride, or alternatively, in theabsence of a catalyst. Preferred ethylene chlorination catalysts forpreparing vinyl chloride comprise a metal halide or metal oxyhalide, andpreferably, a halide or oxyhalide of Cu, Fe or Cr. In an oxychlorinationreaction, a gaseous oxidant and HCl or other chlorinating agent arepreferably co-fed to the reaction zone, and ethylene is oxychlorinatedin the presence of a catalyst having activity for oxychlorinatingethylene to vinyl chloride. Preferred ethylene oxychlorination catalystsfor preparing vinyl chloride comprise a metal halide or metal oxyhalide,and most preferably, a halide or oxyhalide of Cu, Fe or Cr. EthyleneOxide. Ethylene can be oxidized to form ethylene oxide according tomethods known in the art using a catalyst comprising an element orcompound having activity for oxidizing ethylene to ethylene oxide. Thecatalyst preferably comprises Ag, a halide thereof, an oxide thereof ora salt thereof. Ethylene Glycol. Ethylene glycol can be produced byoxidizing ethylene to form ethylene oxide as described above, andhydrating ethylene oxide to form ethylene glycol. Alternatively,ethylene can be converted into ethylene glycol directly, in asingle-step process. Ethylene Carbonate. Ethylene carbonate can beproduced from ethylene by reacting ethylene with carbon dioxide orcarbon monoxide to form ethylene carbonate, or alternatively by formingethylene glycol as described above and then reacting the ethylene glycolwith phosgene. Ethyl acetate. Ethyl acetate can be formed from aceticacid, prepared as described above, according to methods known in theart. Vinyl acetate. Vinyl acetate can be prepared by vapor-phasereaction of ethylene, acetic acid and oxygen over a Pd catalyst.

Propylene produced by the oxydehydrogenation of propane using the nickeloxide/mixed-metal oxide catalyst of the present invention can, forexample, be further reacted to form polypropylene, acrolein, acrylicacid, acetone, propylene oxide and propylene carbonate, among otherdownstream reaction products of propylene. More specifically, propylenecan be formed by oxidatively dehydrogenating propane in the presence ofa catalyst comprising (i) Ni, a Ni oxide, a Ni salt or mixtures thereof,and (ii) elements or compounds selected from the group consisting of Ti,Ta, Nb, Hf, W, Y, Zn, Zr, Al, oxides thereof, and salts thereof, ormixtures of such elements or compounds. The catalyst can be morespecifically characterized as described above. The propylene can beoptionally purified, and then further reacted according to one or moreof the following schemes.

Polypropylene. Propylene can be polymerized to form polypropyleneaccording to methods known in the art using a catalyst having activityfor polymerizing propylene to polypropylene. Exemplary propylenepolymerization catalysts include, for example, aluminum alkyl catalysts.Acrolein. Propylene can be oxidized to form acrolein according tomethods known in the art using a catalyst comprising an element orcompound having activity for oxidizing propylene to acrolein. Thecatalyst preferably comprises an oxide of Bi, Mo, Te or W, or mixturesof such oxides. Acrylic Acid. Propylene can be oxidized to form acrylicacid according to methods known in the art using a catalyst comprisingan element or compound having activity for oxidizing propylene toacrylic acid. The catalyst preferably comprises an oxide of Mo, V or W,or mixtures of such oxides. Acetone. Acetone can be produced frompropylene by oxidation of propylene. Propylene Oxide. Propylene can beoxidized to form propylene oxide according to methods known in the artusing a catalyst comprising an element or compound having activity foroxidizing propylene to propylene oxide. The catalyst preferablycomprises TiSi oxide or PdTiSi oxide catalysts. Propylene carbonate.Propylene carbonate can be formed by preparing propylene oxide asdescribed above, and by reacting the propylene oxide with carbondioxide. Propylene can also be directly converted to propylene carbonatein a single-step process.

The oxydehydrogenation products of isobutane and n-butane can likewisebe further reacted. Isobutene can be further reacted, for example, toform methacrylic acid. n-Butene can be further reacted, for example, toform butanol, butanediol, butadiene, methylethylketone (MEK),methylvinylketone (MVK), furane, or crotonaldehyde. More specifically,isobutene or n-butene can be formed by oxidatively dehydrogenating therespective butane in the presence of a catalyst comprising (i) Ni, a Nioxide, a Ni salt or mixtures thereof, and (ii) elements or compoundsselected from the group consisting of Ti, Ta, Nb, Hf, W, Y, Zn, Zr, Al,oxides thereof, and salts thereof, or mixtures of such elements orcompounds. The catalyst can be more specifically characterized asdescribed above. The isobutene or n-butene can be optionally purified,and then further reacted according to one or more of the followingschemes.

Methacrylic Acid. Isobutene can be oxidized to form methacrylic acidaccording to methods known in the art using a catalyst comprising anelement or compound having activity for oxidizing isobutene tomethacrylic acid. The catalyst preferably comprises a polyoxometallate(POM), and in particular, PVMo- or PVW-containing POM. Butanol. Butanolcan be prepared by hydrating n-butene to form butanol. Butadiene.n-Butene can be oxidatively dehydrogenated to form butadiene accordingto the methods of the present invention (and/or according to othermethods known in the art) using a catalyst comprising an element orcompound having activity for oxidatively dehydrogenating n-butene tobutadiene. The catalyst preferably comprises (i) Ni, a Ni oxide, a Nisalt or mixtures thereof, and (ii) elements or compounds selected fromthe group consisting of Ti, Ta, Nb, Hf, W, Y, Zn, Zr, Al, oxidesthereof, and salts thereof, or mixtures of such elements or compounds.The catalyst can be more specifically characterized as described above.Butanediol. Butane diol can be prepared by forming butadiene, asdescribed above, and then hydrating butadiene to form butanediol.Methylethylketone (MEK). n-Butene can be oxidatively dehydrogenated toform butadiene (as described above), and butadiene can be oxidized toform methylethylketone (MEK) according to the methods known in the artusing a catalyst comprising an element or compound having activity foroxidation of butadiene to MEK. The catalyst preferably comprises Bi/Mo,Mo/V/W, VPO or a polyoxometallate. Methylvinylketone (MVK). n-Butene canbe oxidatively dehydrogenated to form butadiene (as described above),and butadiene can be oxidized to form methylvinylketone (MVK) accordingto the methods known in the art using a catalyst comprising an elementor compound having activity for oxidation of butadiene to MVK. Thecatalyst preferably comprises Bi/Mo, Mo/V/W, VPO or a polyoxometallate.Furane. Furane can be prepared by oxidizing n-butene. Crotonaldehyde.Crotonaldehyde can be prepared by forming butadiene, as described above,and then oxidizing butadiene to form crotonaldehyde.

In each of the aforementioned further reactions of theoxydehydrogenation products (e.g., ethylene, propylene, butenes), thereactants are preferably provided to the reaction zone in the presenceof the respective catalysts. The catalyst(s) for the downstreamreaction(s) can be co-catalysts provided to the same reaction zone inwhich the oxydehydrogenation catalyst is situated, or alternatively, canbe provided to a physically separate, down-stream reaction zone. Ifprovided as a co-catalyst in the same reaction zone, the catalyst forthe downstream reaction can be prepared and provided to the reactionzone as a separate composition from the catalyst of the presentinvention, or alternatively, can be prepared and provided to thereaction zone as a single composition in separate phases or as anintegrated catalyst composition having activity for both theoxydehydrogenation reaction and the respective downstream reaction ofinterest. Regardless of whether the oxydehydrogenation reaction and thedownstream reaction of interest are carried out in the same or inseparate reaction zones, the oxydehydrogenation reaction and thedownstream reaction(s) are preferably performed sequentially (e.g.,where an alkane is oxydehydrogenated to form the corresponding alkene asthe oxydehydrogenation product, and the alkene is then further reactedto form the downstream product of interest).

The following examples illustrate the principles and advantages of theinvention.

EXAMPLES

General.

In general, catalysts were prepared in small quantities (e.g. ˜100 mg)or in larger, bulk quantities (e.g., ˜20 g) using conventionalprecipitation and/or evaporation approaches. Small quantity catalystswere generally prepared with automated liquid dispensing robots (CavroScientific Instruments) in glass vials contained in wells of an aluminumsubstrate. Catalysts were screened for activity for oxidativedehydrogenation of ethane (ODHE), regardless of the scale ofpreparation, in a parallel fixed bed reactor substantially as disclosedin PCT patent application WO 99/64160 (Symyx Technologies, Inc.).

Example 1 ODHE Over NiNbTi Oxide and NiTaTi Oxide Catalysts(#14839/15156)

Catalysts were prepared in small quantities (˜100 mg) from nickelnitrate ([Ni]=1.0 M), titanium oxalate ([Ti]=0.713 M), niobium oxalate([Nb]=0.569 M), and tantalum oxalate ([Ta]=0.650 M) aqueous stocksolutions by precipitation with tetramethylammonium hydroxide([NMe₄OH]=1.44M). Briefly, a library of catalyst precursors wereprepared by dispensing various amounts of aqueous stock solutions usinga Cavro automated liquid handling robot to an array of glass vials heldin an aluminum substrate. The precipitating agent, NMe₄OH solution, wasadded to the various catalyst precursor compositions in about 1.3equivalent of acid and metal ions, by high-speed injection from asyringe head. The high-speed injection of the base provides mixing ofthe catalyst precursor solution and precipitation agents, therebyeffecting precipitation of solid catalyst materials. To further insurewell mixing, additional liquid (e.g., distilled water was, in somecases, also injected into the vial containing the metal precursorsolution and base precipitating agent. The resulting precipitatemixtures were allowed to settle at about 25° C. for about 2 hours, andwere then centrifuged at 3000 rpm to separate solid precipitate from thesolution. The solution was decanted and solids were dried under vacuumat 60° C. in a vacuum oven. Table 1A summarizes the composition andamounts of the various catalyst compositions.

In a first set of experiments, the dried catalyst compositions werecalcined to 300° C. in an atmosphere of air with an oven temperatureprofile: ramp to 300° C. at 2° C./min and dwell at 300° C. for 8 hours.Samples were ground with a spatula. The mixed metal oxide catalysts (˜50mg) were screened in the fixed bed parallel reactor. The performancecharacteristics of these catalysts for ethane oxidative dehydrogenationat 300° C. with relative flowrates of ethane:nitrogen:oxygen of0.42:0.54:0.088 sccm are summarized in Table 1B (ethane conversion) andTable 1C (ethylene selectivity).

After initial screening, these catalyst were subsequently recalcined to400° C. with a similar temperature profile. The performancecharacteristics of these catalysts for ethane oxidative dehydrogenationin the parallel fixed bed reactor at 300° C. with relative flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm are summarized in Table1D (ethane conversion) and Table 1E (ethylene selectivity).

TABLE 1A Catalyst composition (mole fraction) of Ni—Nb—Ti and Ni—Ta—Tioxide mixtures and sample mass, “m” (mg) used in parallel fixed bedreactor screen. Row Col 1 2 3 4 5 6 1 Ni 1.0000 0.8969 0.7944 0.69270.5917 0.4914 Nb 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Ta 0.00000.1031 0.2056 0.3073 0.4083 0.5086 Ti 0.0000 0.0000 0.0000 0.0000 0.00000.0000 m 49.5 50.4 50 49.4 50.1 50.1 2 Ni 0.9119 0.9091 0.8052 0.70210.5997 0.4980 Nb 0.0881 0.0000 0.0000 0.0000 0.0000 0.0000 Ta 0.00000.0000 0.1042 0.2076 0.3103 0.4124 Ti 0.0000 0.0909 0.0906 0.0903 0.09000.0896 m 50.2 49.5 50.3 50.5 49.6 49.8 3 Ni 0.8214 0.8188 0.8163 0.71170.6079 0.5048 Nb 0.1786 0.0890 0.0000 0.0000 0.0000 0.0000 Ta 0.00000.0000 0.0000 0.1052 0.2097 0.3135 Ti 0.0000 0.0921 0.1837 0.1830 0.18240.1817 m 49.5 49.5 49.3 50.4 50 50.3 4 Ni 0.7284 0.7261 0.7239 0.72160.6163 0.5118 Nb 0.2716 0.1805 0.0900 0.0000 0.0000 0.0000 Ta 0.00000.0000 0.0000 0.0000 0.1063 0.2119 Ti 0.0000 0.0934 0.1861 0.2784 0.27740.2764 m 49.3 49.4 49.3 50.1 49.4 49.3 5 Ni 0.6329 0.6309 0.6289 0.62700.6250 0.5189 Nb 0.3671 0.2744 0.1824 0.0909 0.0000 0.0000 Ta 0.00000.0000 0.0000 0.0000 0.0000 0.1074 Ti 0.0000 0.0946 0.1887 0.2821 0.37500.3736 m 50.3 50.3 49.3 49.9 49.6 50.4 6 Ni 0.5348 0.5330 0.5314 0.52970.5280 0.5263 Nb 0.4652 0.3710 0.2774 0.1843 0.0919 0.0000 Ta 0.00000.0000 0.0000 0.0000 0.0000 0.0000 Ti 0.0000 0.0959 0.1913 0.2860 0.38010.4737 m 50.7 22.6 50.4 49.5 49.9 50.6

TABLE 1B Ethane conversion for the catalysts in Table 1A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42/0.54/0.088sccm. Ethane Conversion (%) of Ni—Nb—Ta—Ti Oxide Mixtures 1 2 3 4 5 6 19.4 17.9 19.0 19.1 18.6 16.8 2 16.3 15.7 18.1 17.1 17.6 19.2 3 18.6 18.318.9 17.6 19.3 18.6 4 19.4 18.2 19.4 18.6 18.9 19.2 5 19.4 18.9 16.519.1 18.6 17.1 6 19.0 16.2 17.9 18.0 16.8 16.8

TABLE 1C Ethylene selectivity for the catalysts in Table 1A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42/0.54/0.088sccm. Ethylene Selectivity (%) of Ni—Nb—Ta—Ti Oxide Mixtures 1 2 3 4 5 61 47.2 82.8 84.3 83.7 84.7 83.3 2 79.5 78.5 84.2 85.0 81.2 84.9 3 84.583.6 83.5 84.1 84.4 85.0 4 84.2 84.1 83.4 84.1 84.8 84.8 5 84.8 84.982.1 82.3 82.1 83.8 6 82.6 81.1 79.9 80.5 78.8 79.0

TABLE 1D Ethane conversion for the catalysts in Table 1A but recalcinedto 400° C. Test conditions: 300° C. with ethane/nitrogen/oxygen flow of0.42/0.54/0.088 sccm. Ethane Conversion (%) of Ni—Nb—Ta—Ti OxideMixtures 1 2 3 4 5 6 1 5.8 11.9 12.2 12.4 11.8 9.6 2 9.8 9.2 11.5 9.211.3 13.0 3 12.0 12.7 11.1 12.0 13.8 12.3 4 12.8 11.5 13.3 11.1 10.111.9 5 13.5 12.0 12.9 11.1 11.9 10.4 6 13.0 9.0 13.0 13.6 11.3 11.0

TABLE 1E Ethylene selectivity for the catalysts in Table 1A butrecalcined to 400° C. Test conditions: 300° C. withethane/nitrogen/oxygen flow of 0.42/0.54/0.088 sccm. EthyleneSelectivity (%) of Ni—Nb—Ta—Ti Oxide Mixtures 1 2 3 4 5 6 1 34.2 83.185.4 84.4 85.2 85.1 2 77.2 75.3 84.9 86.4 80.8 84.6 3 85.1 84.1 82.784.0 83.8 84.1 4 85.4 84.5 83.7 82.2 83.9 84.5 5 86.4 85.9 79.3 78.780.4 83.1 6 80.1 78.4 79.3 77.1 72.1 71.2

Another library of NiNbTi oxide catalysts was prepared substantially asdescribed above and having the composition and amounts summarized inTable 1F. The performance characteristics of these catalysts for ethaneoxidative dehydrogenation in the parallel fixed bed reactor at 300° C.with relative flowrates of ethane:nitrogen:oxygen of 0:42:0.54:0.088sccm are summarized in Table 1G (ethane conversion) and Table 1H(ethylene selectivity).

TABLE 1F Catalyst composition (mole fractions) of NiNbTi oxide catalystsand sample mass (mg) used in parallel fixed bed reactor screen. RowColumn 1 2 3 4 5 6 1 Ni 1.000 Nb 0.000 Ti 0.000 mass 49.9 (mg) 2 Ni0.841 0.885 Nb 0.000 0.115 Ti 0.159 0.000 mass 45.0 56.3 (mg) 3 Ni 0.7140.748 0.784 Nb 0.000 0.103 0.216 Ti 0.286 0.150 0.000 mass 49.2 49.345.0 (mg) 4 Ni 0.612 0.637 0.665 0.696 Nb 0.000 0.093 0.194 0.304 Ti0.388 0.270 0.141 0.000 mass 49.6 51.4 51.9 50.8 (mg) 5 Ni 0.526 0.5460.568 0.592 0.617 Nb 0.000 0.085 0.176 0.275 0.383 Ti 0.474 0.369 0.2560.133 0.000 mass 44.9 46.3 46.7 44.0 47.0 (mg) 6 Ni 0.455 0.471 0.4880.506 0.526 0.547 Nb 0.000 0.078 0.161 0.251 0.348 0.453 Ti 0.545 0.4520.351 0.243 0.126 0.000 mass 48.8 50.5 46.1 48.5 52.0 54.1 (mg)

TABLE 1G Ethane conversion for catalysts listed in Table 1F. Testconditions: 300° C. with ethane:nitrogen:oxygen flow of 0.42:0.54:0.088sccm. 1 2 3 4 5 6 1 8.4 2 16.6 18.2 3 17.5 16.5 16.9 4 16.7 16.3 17.016.1 5 15.9 16.2 17.1 15.9 17.9 6 16.6 17.5 15.5 15.2 17.2 14.4

TABLE 1H Ethylene selectivity for catalysts listed in Table 1F. Testconditions: 300° C. with ethane:nitrogen:oxygen flow of 0.42:0.54:0.088sccm. 1 2 3 4 5 6 1 43.3 2 81.5 82.8 3 83.1 81.9 82.5 4 82.5 77.2 83.183.5 5 77.8 78.4 77.9 78.1 80.6 6 77.8 76.9 75.4 78.8 80.1 73.0

Example 2 ODHE Over NiNbTaTi Oxide Catalysts (#16160/16223)

Catalyst compositions comprising various relative amounts of oxides ofNi, Nb, Ta and Ti were prepared in small (˜100 mg) quantities byprecipitation substantially as described in connection with Example 1.Table 2A summarizes the composition and amounts of the various catalystcompositions.

In a first set of experiments, the dried catalyst compositions werecalcined to 300° C. in an atmosphere of air with an oven temperatureprofile: ramp to 300° C. at 2° C./min and dwell at 300° C. for 8 hours.The mixed metal oxide catalysts (˜50 mg) were screened in the fixed bedparallel reactor. The performance characteristics of these catalysts forethane oxidative dehydrogenation at 300° C. with relative flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm are summarized in Table2B (ethane conversion) and Table 2C (ethylene selectivity). Thecatalysts were also screened for ethane oxidative dehydrogenation at300° C. with relative flowrates of ethane:nitrogen:oxygen of0.42:0.82:0.022 sccm. The performance characteristics for theseexperiments are summarized in Table 2D (ethane conversion) and Table 2E(ethylene selectivity).

After these screenings, these catalyst were subsequently recalcined to400° C. for 8 hours with a similar temperature profile. The performancecharacteristics of these catalysts for ethane oxidative dehydrogenationin the parallel fixed bed reactor at 300° C. with relative flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm are summarized in Table2F (ethane conversion) and Table 2G (ethylene selectivity). Therecalcined catalysts were also screened for ethane oxidativedehydrogenation at 300° C. with relative flowrates ofethane:nitrogen:oxygen of 0.42:0.82:0.022 sccm. The performancecharacteristics for these experiments are summarized in Table 2H (ethaneconversion) and Table 2I (ethylene selectivity).

TABLE 2A Catalyst composition (mole fraction) and sample mass, “m” (mg)of bulk NiNbTaTi Oxide Mixtures Row Col 1 2 3 4 5 6 1 Ni 0.6014 0.57140.5418 0.5124 0.4832 0.4542 Nb 0.1065 0.1188 0.1310 0.1431 0.1550 0.1669Ta 0.0948 0.1133 0.1317 0.1498 0.1679 0.1857 Ti 0.1973 0.1964 0.19560.1948 0.1939 0.1931 m 50.0 50.0 50.3 50.5 49.5 50.5 2 Ni 0.4889 0.47300.4559 0.4375 0.4176 0.3959 Nb 0.0808 0.1089 0.1392 0.1718 0.2071 0.2454Ta 0.2699 0.2518 0.2323 0.2113 0.1886 0.1639 Ti 0.1604 0.1662 0.17260.1794 0.1868 0.1948 m 49.5 50.6 50.0 50.5 49.6 49.4 3 Ni 0.6004 0.57310.5448 0.5154 0.4849 0.4532 Nb 0.1163 0.1279 0.1399 0.1524 0.1654 0.1788Ta 0.1295 0.1424 0.1557 0.1696 0.1840 0.1990 Ti 0.1538 0.1566 0.15950.1626 0.1657 0.1689 m 49.9 49.3 49.5 49.6 49.7 50.0 4 Ni 0.6435 0.61350.5835 0.5535 0.5234 0.4934 Nb 0.1173 0.1315 0.1457 0.1598 0.1740 0.1882Ta 0.1306 0.1463 0.1621 0.1779 0.1937 0.2095 Ti 0.1086 0.1087 0.10870.1088 0.1089 0.1089 m 49.5 49.3 49.6 49.5 50.1 50.3

TABLE 2B Ethane conversion for the catalysts in Table 2A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42:0.54:0.088sccm. Ethane Conversion (%) of Ni—Nb—Ta—Ti Oxide Mixtures 1 2 3 4 5 6 110.7 17.0 18.1 19.4 19.2 13.6 2 9.0 17.5 18.7 16.8 19.0 15.6 3 12.1 17.519.0 19.0 19.1 16.8 4 7.8 16.8 19.5 18.8 17.7 18.2

TABLE 2C Ethylene selectivity for the catalysts in Table 2A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42/0.54/0.088sccm. Ethylene Selectivity (%) of Ni—Nb—Ta—Ti Oxide Mixtures 1 2 3 4 5 61 82.9 83.1 84.3 85.1 84.2 83.2 2 80.4 86.6 85.1 84.7 84.5 84.1 3 70.984.4 84.9 84.7 84.6 84.0 4 76.9 84.7 84.8 84.5 84.8 85.0

TABLE 2D Ethane conversion for the catalysts in Table 2A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42/0.082/0.022sccm. Ethane Conversion (%) of Ni—Nb—Ta—Ti Oxide Mixtures 1 2 3 4 5 6 110.5 11.2 11.4 11.9 11.8 11.0 2 8.2 11.4 11.8 11.3 11.9 11.5 3 9.3 11.611.3 11.6 11.8 11.3 4 7.1 11.6 12.0 11.6 11.7 11.4

TABLE 2E Ethylene selectivity for the catalysts in Table 2A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42/0.082/0.022sccm. Ethylene Selectivity (%) of Ni—Nb—Ta—Ti Oxide Mixtures 1 2 3 4 5 61 91.6 92.7 92.9 93.5 92.9 92.5 2 90.1 93.4 93.3 93.4 93.2 92.6 3 86.793.0 93.5 93.3 93.3 92.7 4 87.7 93.4 93.4 93.0 93.2 92.9

TABLE 2F Ethane conversion for the catalysts in Table 2A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42/0.54/0.088sccm. Ethane Conversion (%) of Ni—Nb—Ta—Ti Oxide Mixtures 1 2 3 4 5 6 15.6 12.3 13.2 14.1 14.6 7.1 2 4.9 14.7 13.5 11.4 15.0 8.7 3 8.1 12.613.3 14.6 14.6 11.1 4 3.7 10.4 14.3 14.8 14.8 14.4

TABLE 2G Ethylene selectivity for the catalysts in Table 2A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42/0.54/0.088sccm. Ethylene Selectivity (%) of Ni—Nb—Ta—Ti Oxide Mixtures 1 2 3 4 5 61 83.4 80.9 82.1 84.1 83.8 84.9 2 81.6 83.9 84.3 84.5 83.6 85.1 3 67.983.5 83.7 83.6 83.6 84.5 4 78.5 84.7 83.8 83.2 83.6 84.5

TABLE 2H Ethane conversion for the catalysts in Table 2A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42/0.082/0.022sccm. Ethane Conversion (%) of Ni—Nb—Ta—Ti Oxide Mixtures 1 2 3 4 5 6 15.7 10.7 8.4 11.5 11.9 7.6 2 5.3 10.2 11.1 10.7 11.7 8.6 3 8.4 11.3 11.211.5 11.8 10.6 4 4.1 10.1 11.7 11.6 11.3 11.2

TABLE 2I Ethylene selectivity for the catalysts in Table 2A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42/0.082/0.022sccm. Ethylene Selectivity (%) of Ni—Nb—Ta—Ti Oxide Mixtures 1 2 3 4 5 61 88.9 92.1 92.4 93.2 92.8 90.9 2 87.4 93.2 93.1 93.0 93.2 91.7 3 85.792.5 93.0 93.2 93.0 92.3 4 85.5 92.6 93.1 92.9 93.1 92.9

Example 3 ODHE Over NiNbZr/NiTaZr Oxide Catalysts (#14840/15157)

Catalysts were prepared in small quantities (˜100 mg) from nickelnitrate ([Ni]=1.0 M), niobium oxalate ([Nb]=0.569 M), tantalum oxalate([Ta]=0.650 M), and zirconium oxalate ([Zr]=0.36 M) aqueous stocksolutions by precipitation with tetraethylammonium hydroxide. The solidmaterials were separated from solution by centrifugation. Thesupernatant was decanted and solid materials were dried at 60° C. undera reduced atmosphere. Table 3A summarizes the composition and amounts ofthe various catalyst compositions.

In a first set of experiments, the dried catalyst compositions werecalcined to 300° C. in an atmosphere of air with an oven temperatureprofile: ramp to 300° C. at 2° C./min and dwell at 300° C. for 8 hours.The mixed metal oxide catalysts (˜50 mg) were screened in the fixed bedparallel reactor. The performance characteristics of these catalysts forethane oxidative dehydrogenation at 300° C. with relative flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm are summarized in Table3B (ethane conversion) and Table 3C (ethylene selectivity).

After initial screening, these catalyst were subsequently recalcined to400° C. with a similar temperature profile. The performancecharacteristics of these catalysts for ethane oxidative dehydrogenationin the parallel fixed bed reactor at 300° C. with relative flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm are summarized in Table3D (ethane conversion) and Table 3E (ethylene selectivity).

TABLE 3A Catalyst composition (mole fraction) of Ni—Nb—Zr and Ni—Ta—Zroxide mixtures & sample mass, “m” (mg) used in parallel fixed bedreactor screen. Row Col 1 2 3 4 5 6 1 Ni 1.0000 0.8969 0.7944 0.69270.5917 0.4914 Nb 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Ta 0.00000.1031 0.2056 0.3073 0.4083 0.5086 Zr 0.0000 0.0000 0.0000 0.0000 0.00000.0000 m 49.8 49.5 49.6 49.6 50.1 49.5 2 Ni 0.9119 0.9328 0.8262 0.72030.6152 0.5108 Nb 0.0881 0.0000 0.0000 0.0000 0.0000 0.0000 Ta 0.00000.0000 0.1069 0.2130 0.3184 0.4230 Zr 0.0000 0.0672 0.0669 0.0667 0.06640.0662 m 49.3 49.6 50.4 49.9 50.3 49.3 3 Ni 0.8214 0.8405 0.8606 0.75020.6406 0.5319 Nb 0.1786 0.0914 0.0000 0.0000 0.0000 0.0000 Ta 0.00000.0000 0.0000 0.1109 0.2210 0.3303 Zr 0.0000 0.0681 0.1394 0.1389 0.13840.1379 m 49.8 50.6 50.5 49.5 50.6 49.9 4 Ni 0.7284 0.7456 0.7637 0.78260.6682 0.5547 Nb 0.2716 0.1853 0.0949 0.0000 0.0000 0.0000 Ta 0.00000.0000 0.0000 0.0000 0.1153 0.2296 Zr 0.0000 0.0690 0.1414 0.2174 0.21650.2157 m 50.1 49.4 49.5 49.6 49.5 50.6 5 Ni 0.6329 0.6481 0.6640 0.68070.6983 0.5796 Nb 0.3671 0.2819 0.1926 0.0987 0.0000 0.0000 Ta 0.00000.0000 0.0000 0.0000 0.0000 0.1200 Zr 0.0000 0.0700 0.1434 0.2206 0.30170.3005 m 50.3 49.6 49.8 49.5 49.9 49.7 6 Ni 0.5348 0.5478 0.5614 0.57580.5909 0.6068 Nb 0.4652 0.3812 0.2931 0.2004 0.1028 0.0000 Ta 0.00000.0000 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.0710 0.1455 0.2239 0.30630.3932 m 50.0 49.8 50.3 50.6 50.0 49.9

TABLE 3B Ethane conversion for the catalysts in Table 3A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42/0.54/0.088sccm. Ethane Conversion (%) of Ni—Nb—Ta—Zr Oxide Mixtures 1 2 3 4 5 6 19.1 18.2 18.9 19.2 18.6 15.7 2 16.0 14.8 18.0 16.4 17.3 19.5 3 18.4 18.115.4 17.6 13.1 16.7 4 19.3 19.1 16.7 14.7 15.2 15.3 5 19.4 19.0 13.715.3 13.6 16.1 6 18.9 19.0 12.1 11.3 12.7 12.4

TABLE 3C Ethylene Selectivity for the catalysts in Table 3A. Testconditions: 300° C. with ethane/nitrogen/oxygen flow of 0.42/0.54/0.088sccm. Ethane Selectivity (%) of Ni-Nb-Ta-Zr Oxide Mixtures 1 2 3 4 5 6 146.0 83.8 84.4 84.0 84.8 83.0 2 80.4 74.4 83.4 81.1 80.7 83.6 3 84.883.7 77.2 81.8 73.9 81.5 4 84.4 84.2 79.5 76.6 73.6 79.1 5 84.7 82.973.4 76.6 73.4 79.3 6 82.7 84.6 73.9 70.2 73.9 76.5

TABLE 3D Ethane Conversion for the catalysts in Table 3A but recalcinedto 400° C.. Test conditions: 300° C. with ethane/nitrogen/oxygen flow of0.42/0.54/0.088 sccm. Ethane Conversion (%) of Ni-Nb-Ta-Zr OxideMixtures 1 2 3 4 5 6 1 6.3 12.2 12.6 12.5 11.9 8.9 2 9.1 10.8 12.2 10.811.4 15.1 3 12.2 13.8 10.2 11.9 8.0 11.2 4 13.2 13.2 11.4 8.8 10.3 10.85 13.6 13.5 8.6 11.2 9.2 12.2 6 14.7 13.4 7.5 6.4 8.0 7.5

TABLE 3E Ethylene Selectivity for the catalysts in Table 3A butrecalcined to 400° C. Test conditions: 300° C. withethane/nitrogen/oxygen flow of 0.42/0.54/0.088 sccm. EthyleneSelectivity (%) of Ni-Nb-Ta-Zr Oxide Mixtures 1 2 3 4 5 6 1 33.4 83.385.4 84.6 86.0 86.7 2 78.8 66.2 83.3 81.0 80.9 83.5 3 86.4 84.1 70.680.2 72.9 81.1 4 85.8 84.8 78.6 69.1 69.3 78.5 5 86.5 83.7 71.9 75.869.7 77.0 6 80.4 82.9 72.3 62.9 71.7 74.9

Example 4 ODHE Over NiTiZr Oxide Catalysts (#14332)

Catalysts were prepared in small quantities (˜100 mg) from nickelnitrate ([Ni]=1.0 M), titanium oxalate ([Ti]=0.713 M) and zirconiumoxalate ([Zr]=0.36 M) aqueous stock solutions by precipitation withtetramethylammonium hydroxide. The solid materials were separated fromsolution by centrifugation. The supernatant was decanted and solidmaterials were dried at 60° C. under a reduced atmosphere. Table 4Asummarizes the composition and amounts of the various catalystcompositions.

In a first set of experiments, the dried catalyst compositions werecalcined to 300° C. in an atmosphere of air with an oven temperatureprofile: ramp to 300° C. at 2° C./min and dwell at 300° C. for 8 hours.The mixed metal oxide catalysts (˜50 mg) were screened in the fixed bedparallel reactor. The performance characteristics of these catalysts forethane oxidative dehydrogenation at 300° C. with relative flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm are summarized in Table4B (ethane conversion) and Table 4C (ethylene selectivity).

TABLE 4A Catalyst composition (mole fraction) of NiTiZr oxide catalystsand sample mass (mg) used in parallel fixed bed reactor screen. RowColumn 1 2 3 4 5 6 1 Ni 1.000 Zr 0.000 Ti 0.000 mass 54.1 (mg) 2 Ni0.930 0.913 Zr 0.070 0.000 Ti 0.000 0.087 mass 52.3 47.6 (mg) 3 Ni 0.8620.847 0.833 Zr 0.138 0.068 0.000 Ti 0.000 0.085 0.167 mass 54.8 50.352.3 (mg) 4 Ni 0.797 0.784 0.771 0.759 Zr 0.203 0.133 0.065 0.000 Ti0.000 0.083 0.163 0.241 mass 52.0 54.0 47.4 50.2 (mg) 5 Ni 0.735 0.7230.712 0.701 0.690 Zr 0.265 0.195 0.128 0.063 0.000 Ti 0.000 0.081 0.1600.236 0.310 mass 52.0 52.9 45.3 46.4 49.6 (mg) 6 Ni 0.676 0.665 0.6540.644 0.635 0.625 Zr 0.324 0.255 0.188 0.124 0.061 0.000 Ti 0.000 0.0800.157 0.232 0.305 0.375 mass 53.0 45.2 50.6 47.3 51.8 52.5 (mg)

TABLE 4B Ethane conversion for catalysts in Table 4A. Test conditions:300° C. with ethane:nitrogen:oxygen flow of 0.42:0.54:0.088 sccm. 1 2 34 5 6 1 7.9 2 15.5 14.9 3 17.0 16.5 16.6 4 13.3 14.3 17.2 17.3 5 14.215.4 15.8 17.7 20.6 6 12.4 14.9 13.0 13.5 16.1 19.1

TABLE 4C Ethylene selectivity for catalysts in Table 4A. Testconditions: 300° C. with ethane:nitrogen:oxygen flow of 0.42:0.54:0.088sccm. 1 2 3 4 5 6 1 46.1 2 72.9 78.5 3 75.8 76.5 81.9 4 71.3 78.8 81.081.7 5 71.0 74.8 72.1 81.2 84.7 6 69.0 71.3 76.8 70.9 77.7 83.2

Example 5 ODHE Over NiTiCe/NiZrCe Oxide Catalysts (#14841/15158)

Ni—Ti—Ce and Ni—Zr—Ce oxide catalysts were prepared and screened in amanner similar to the catalysts in Examples 1 and 3, using ceriumnitrate ([Ce]=1.00 M) aqueous stock solution. Table 5A summarizes thecomposition and amounts of the various catalyst compositions.

In the initial screening (calcination at 300° C., 8 hours, screening infixed bed parallel reactor at 300° C. with flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, as described), ethaneconversion values for the NiTiCe oxide compositions ranged from 9.6 %(with ethylene selectivity of 66.5%) to 17.6% (with ethylene selectivityof 73.3%), and ethylene selectivity values ranged from 66.5% (withethane conversion of 9.6%) to 80.1% (with ethane conversion of 17.0%).Ethane conversion values for the NiZrCe oxide compositions ranged from13.4% (with ethylene selectivity of 69.1%) to 16.4% (with ethyleneselectivity of 75.9%), and ethylene selectivity values ranged from 69.1%(with ethane conversion of 13.4%) to 78.2% (with ethane conversion of15.4%).

After recalcining (400° C., 8 hours, as described), the catalysts wererescreened (results not shown).

TABLE 5A Catalyst composition (mole fraction) of Ni—Ti—Ce and Ni—Zr—Ceoxide catalysts and sample mass, “m” (mg) used in parallel fixed bedreactor screen. Row Col 1 2 3 4 5 6 1 Ni 1.0000 0.9259 0.8475 0.76420.6757 0.5814 Ti 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Ce 0.00000.0000 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.0741 0.1525 0.2358 0.32430.4186 m 49.5 49.4 49.7 48.6 49.2 49.8 2 Ni 0.9091 0.9474 0.8677 0.78300.6928 0.5967 Ti 0.0909 0.0000 0.0000 0.0000 0.0000 0.0000 Ce 0.00000.0526 0.0542 0.0559 0.0577 0.0597 Zr 0.0000 0.0000 0.0781 0.1611 0.24940.3437 m 50.6 50.7 49.5 50.0 49.7 50.6 3 Ni 0.8163 0.8511 0.8889 0.80280.7109 0.6127 Ti 0.1837 0.0957 0.0000 0.0000 0.0000 0.0000 Ce 0.00000.0532 0.1111 0.1147 0.1185 0.1225 Zr 0.0000 0.0000 0.0000 0.0826 0.17060.2647 m 49.4 49.7 50.5 49.7 49.4 50.3 4 Ni 0.7216 0.7527 0.7865 0.82350.7299 0.6297 Ti 0.2784 0.1935 0.1011 0.0000 0.0000 0.0000 Ce 0.00000.0538 0.1124 0.1765 0.1825 0.1889 Zr 0.0000 0.0000 0.0000 0.0000 0.08760.1814 m 49.9 50.6 50.4 49.3 50.0 50.0 5 Ni 0.6250 0.6522 0.6818 0.71430.7500 0.6477 Ti 0.3750 0.2935 0.2045 0.1071 0.0000 0.0000 Ce 0.00000.0543 0.1136 0.1786 0.2500 0.2591 Zr 0.0000 0.0000 0.0000 0.0000 0.00000.0933 m 49.7 49.6 49.9 50.6 50.1 50.4 6 Ni 0.5263 0.5495 0.5747 0.60240.6329 0.6667 Ti 0.4737 0.3956 0.3103 0.2169 0.1139 0.0000 Ce 0.00000.0549 0.1149 0.1807 0.2532 0.3333 Zr 0.0000 0.0000 0.0000 0.0000 0.00000.0000 m 50.0 49.6 49.9 50.0 50.1 50.4

Example 6 ODHE Over NiTiSb/NiZrSb Oxide Catalysts (#14842/15159)

Ni—Ti—Sb and Ni—Zr—Sb oxide catalysts were prepared and screened in amanner similar to the catalysts in Examples 1 and 3, using antimonyacetate ([Sb]=0.234 M) aqueous stock solution. Table 6A summarizes thecomposition and amounts of the various catalyst compositions.

In the initial screening (calcination at 300° C., 8 hours, screening infixed bed parallel reactor at 300° C. with flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, as described), ethaneconversion values for the NiTiSb oxide compositions ranged from 1.0%(with ethylene selectivity of 73.3%) to 15.8% (with ethylene selectivityof 79.2%), and ethylene selectivity values ranged from 73.3% (withethane conversion of 1.0%) to 81.8% (with ethane conversion of 7.2%).Ethane conversion values for the NiZrSb oxide compositions ranged from1.4% (with ethylene selectivity of 75.5%) to 11.9% (with ethyleneselectivity of 74.7%), and ethylene selectivity values ranged from 63.2%(with ethane conversion of 6.3%) to 78.3% (with ethane conversion of11.3%).

After recalcining (400° C., 8 hours, as described), the catalysts wererescreened (results not shown).

TABLE 6A Catalyst composition (mole fraction) of NiTiSb/NiZrSb oxidemixtures and sample mass, “m” (mg) used in parallel fixed bed reactorscreen. Row Col 1 2 3 4 5 6 1 Ni 1.0000 0.9377 0.8642 0.7764 0.66950.5365 Ti 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.06230.1358 0.2236 0.3305 0.4635 Sb 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000m 49.4 50.6 50.4 50.6 49.3 49.5 2 Ni 0.9233 0.9403 0.8669 0.7790 0.67190.5387 Ti 0.0767 0.0000 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.00000.0681 0.1496 0.2488 0.3724 Sb 0.0000 0.0597 0.0651 0.0715 0.0793 0.0890m 50.4 50.7 50.0 49.4 50.0 50.2 3 Ni 0.8359 0.8523 0.8695 0.7816 0.67440.5409 Ti 0.1641 0.0837 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.00000.0000 0.0750 0.1665 0.2804 Sb 0.0000 0.0640 0.1305 0.1434 0.1591 0.1786m 50.4 50.4 49.2 50.3 49.4 49.7 4 Ni 0.7353 0.7509 0.7672 0.7842 0.67690.5432 Ti 0.2647 0.1802 0.0921 0.0000 0.0000 0.0000 Zr 0.0000 0.00000.0000 0.0000 0.0836 0.1877 Sb 0.0000 0.0689 0.1408 0.2158 0.2395 0.2691m 49.2 49.3 49.8 50.7 50.6 49.8 5 Ni 0.6184 0.6326 0.6475 0.6631 0.67950.5455 Ti 0.3816 0.2928 0.1998 0.1023 0.0000 0.0000 Zr 0.0000 0.00000.0000 0.0000 0.0000 0.0943 Sb 0.0000 0.0746 0.1527 0.2346 0.3205 0.3603m 50.8 49.5 49.3 50.0 50.2 49.7 6 Ni 0.4808 0.4928 0.5055 0.5188 0.53290.5478 Ti 0.5192 0.4258 0.3276 0.2241 0.1151 0.0000 Zr 0.0000 0.00000.0000 0.0000 0.0000 0.0000 Sb 0.0000 0.0814 0.1669 0.2570 0.3520 0.4522m 20.2 50.6 50.5 50.8 50.4 49.0

Example 7 ODHE Over NiTiNd/NiZrNd Oxide Catalysts (#15154/15420)

Ni—Ti—Nd and Ni—Zr—Nd oxide catalysts were prepared and screened in amanner similar to the catalysts in Examples 1 and 3, using neodymiumnitrate ([Nd]=0.50 M) aqueous stock solution. Table 7A summarizes thecomposition and amounts of the various catalyst compositions.

In the initial screening (calcination at 300° C., 8 hours, screening infixed bed parallel reactor at 300° C. with flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, as described), ethaneconversion (C) and ethylene selectivity (S) values for the NiTiNd oxidecompositions ranged from 6.3% C, 45.1% S to 18.1% C, 84.6% S. Ethaneconversion values for the NiZrNd oxide compositions ranged from 4.5%(with ethylene selectivity of 41.5%) to 13.4% (with ethylene selectivityof 71.8%), and ethylene selectivity values ranged from 41.5% (withethane conversion of 4.5%) to 77.3% (with ethane conversion of 13.1%).

In a second screening in the fixed bed parallel reactor at 300° C. withdifferent flowrates (ethane:nitrogen:oxygen of 0.42:0.082:0.022 sccm),ethane conversion (C) and ethylene selectivity (S) values for the NiTiNdoxide compositions ranged from 4.9% C, 62.7% S to 11.0% C, 93.3% S.Ethane conversion (C) and ethylene selectivity (S) values for the NiZrNdoxide compositions ranged from 4.2% C, 59.0% S to 10.0% C, 90.7% S.

After recalcining (400° C., 8 hours, as described), the catalysts wererescreened (results not shown).

TABLE 7A Catalyst composition (mole fraction) of NiTiNd/NiZrNd oxidecatalysts and sample mass, “m” (mg) used in parallel fixed bed reactorscreen. Row Col 1 2 3 4 5 6 1 Ni 1.0000 0.9259 0.8475 0.7642 0.67570.5814 Ti 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.07410.1525 0.2358 0.3243 0.4186 Nd 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000m 49.6 49.7 49.5 49.3 50.3 49.5 2 Ni 0.9259 0.9474 0.8677 0.7830 0.69280.5967 Ti 0.0741 0.0000 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.00000.0781 0.1611 0.2494 0.3437 Nd 0.0000 0.0526 0.0542 0.0559 0.0577 0.0597m 49.9 50.8 50.4 49.4 49.4 50.0 3 Ni 0.8475 0.8677 0.8889 0.8028 0.71090.6127 Ti 0.1525 0.0781 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.00000.0000 0.0826 0.1706 0.2647 Nd 0.0000 0.0542 0.1111 0.1147 0.1185 0.1225m 49.9 49.2 49.4 50.3 49.7 49.4 4 Ni 0.7642 0.7830 0.8028 0.8235 0.72990.6297 Ti 0.2358 0.1611 0.0826 0.0000 0.0000 0.0000 Zr 0.0000 0.00000.0000 0.0000 0.0876 0.1814 Nd 0.0000 0.0559 0.1147 0.1765 0.1825 0.1889m 49.8 49.5 50.0 49.8 49.8 49.8 5 Ni 0.6757 0.6928 0.7109 0.7299 0.75000.6477 Ti 0.3243 0.2494 0.1706 0.0876 0.0000 0.0000 Zr 0.0000 0.00000.0000 0.0000 0.0000 0.0933 Nd 0.0000 0.0577 0.1185 0.1825 0.2500 0.2591m 49.5 49.6 49.8 50.0 49.4 50.1 6 Ni 0.5814 0.5967 0.6127 0.6297 0.64770.6667 Ti 0.4186 0.3437 0.2647 0.1814 0.0933 0.0000 Zr 0.0000 0.00000.0000 0.0000 0.0000 0.0000 Nd 0.0000 0.0597 0.1225 0.1889 0.2591 0.3333m 50.1 49.3 49.5 50.7 50.6 45.0

Example 8 ODHE Over NiTiYb/NiZrYb Oxide Catalysts (#15155/15421)

Ni—Ti—Yb and Ni—Zr—Yb oxide catalysts were prepared and screened in amanner similar to the catalysts in Examples 1 and 3, using ytterbiumnitrate ([Yb]=0.456 M) aqueous stock solution. Table 8A summarizes thecomposition and amounts of the various catalyst compositions.

In the initial screening (calcination at 300° C., 8 hours, screening infixed bed parallel reactor at 300° C. with flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, as described), ethaneconversion (C) and ethylene selectivity (S) values for the NiTiYb oxidecompositions ranged from 4.1% C, 41.6% S to 16.8% C, 83.4% S. Ethaneconversion (C) and ethylene selectivity (S) values for the NiZrYb oxidecompositions ranged from 5.0% C, 46.8% S to 13.2% C, 75.6% S.

In a second screening in the fixed bed parallel reactor at 300° C. withdifferent flowrates (ethane:nitrogen:oxygen of 0.42:0.082:0.022 sccm),ethane conversion (C) and ethylene selectivity (S) values for the NiTiYboxide compositions ranged from 6.0% C, 72.9% S to 10.6% C, 91.8% S.Ethane conversion (C) and ethylene selectivity (S) values for the NiZrYboxide compositions ranged from 6.7% C, 75.9% S to 10.3% C, 89.9% S.

After recalcining (400° C., 8 hours, as described), the catalysts wererescreened (results not shown).

TABLE 8A Catalyst composition (mole fraction) of NiTiYb/NiZrYb oxidecatalysts and sample mass, “m” (mg) used in parallel fixed bed reactorscreen. Row Col 1 2 3 4 5 6 1 Ni 1.0000 0.9259 0.8475 0.7642 0.67570.5814 Ti 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.07410.1525 0.2358 0.3243 0.4186 Yb 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000m 50.0 — — — — — 2 Ni 0.9091 0.9518 0.8718 0.7869 0.6964 0.5998 Ti0.0909 0.0000 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.0000 0.0785 0.16190.2507 0.3455 Yb 0.0000 0.0482 0.0497 0.0513 0.0529 0.0547 m 49.3 49.650.1 50.0 49.4 50.3 3 Ni 0.8163 0.8551 0.8977 0.8109 0.7184 0.6194 Ti0.1837 0.0962 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.0000 0.0000 0.08340.1724 0.2676 Yb 0.0000 0.0487 0.1023 0.1057 0.1092 0.1130 m 49.7 49.349.8 50.0 49.5 49.1 4 Ni 0.7216 0.7563 0.7944 0.8365 0.7418 0.6404 Ti0.2784 0.1945 0.1021 0.0000 0.0000 0.0000 Zr 0.0000 0.0000 0.0000 0.00000.0890 0.1844 Yb 0.0000 0.0493 0.1035 0.1635 0.1691 0.1752 m 49.5 50.349.3 49.8 50.2 50.6 5 Ni 0.6250 0.6553 0.6887 0.7257 0.7669 0.6628 Ti0.3750 0.2949 0.2066 0.1089 0.0000 0.0000 Zr 0.0000 0.0000 0.0000 0.00000.0000 0.0954 Yb 0.0000 0.0498 0.1047 0.1655 0.2331 0.2418 m 49.3 49.950.0 49.5 50.6 49.8 6 Ni 0.5263 0.5521 0.5806 0.6121 0.6473 0.6868 Ti0.4737 0.3975 0.3135 0.2204 0.1165 0.0000 Zr 0.0000 0.0000 0.0000 0.00000.0000 0.0000 Yb 0.0000 0.0504 0.1059 0.1675 0.2361 0.3132 m 49.4 49.650.3 49.6 50.5 49.8

Example 9 ODHE Over NiTiSm/NiZrSm Oxide Catalysts (#15935/16221)

Ni—Ti—Sm and Ni—Zr—Sm oxide catalysts were prepared and screened in amanner similar to the catalysts in Examples 1 and 3, using samariumnitrate ([Sm]=0.506 M) aqueous stock solution. Table 9A summarizes thecomposition and amounts of the various catalyst compositions.

In the initial screening (calcination at 300° C., 8 hours, screening infixed bed parallel reactor at 300° C. with flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, as described), ethaneconversion values for the NiTiSm oxide compositions ranged from 10.4%(with ethylene selectivity of 57.5%) to 19.0% (with ethylene selectivityof 81.8%), and ethylene selectivity values ranged from 57.5% (withethane conversion of 10.4%) to 82.8% (with ethane conversion of 18.3%).Ethane conversion values for the NiZrSm oxide compositions ranged from11.5% (with ethylene selectivity of 60.7%) to 13.7% (with ethyleneselectivity of 71.0%), and ethylene selectivity values ranged from 60.7%(with ethane conversion of 11.5%) to 76.7% (with ethane conversion of13.4%).

In a second screening in the fixed bed parallel reactor at 300° C. withdifferent flowrates (ethane:nitrogen:oxygen of 0.42:0.082:0.022 sccm),ethane conversion values for the NiTiSm oxide compositions ranged from6.8% (with ethylene selectivity of 75.1%) to 11.5% (with ethyleneselectivity of 92.2%), and ethylene selectivity values ranged from 75.1%(with ethane conversion of 6.8%) to 92.7% (with ethane conversion of11.3%). Ethane conversion (C) and ethylene selectivity (S) values forthe NiZrSm oxide compositions ranged from 7.7% C, 80.3% S to 10.3% C,90.4% S.

After recalcining (400° C., 8 hours, as described), the catalysts wererescreened (results not shown).

TABLE 9A Catalyst composition (mole fraction) of NiTiSm/NiZrSm oxidecatalysts and sample mass, “m” (mg) used in parallel fixed bed reactorscreen. Row Col 1 2 3 4 5 6 1 Ni 1.0000 0.9259 0.8475 0.7642 0.67570.5814 Ti 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.07410.1525 0.2358 0.3243 0.4186 Sm 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000m 49.6 49.8 50.0 50.5 50.3 50.0 2 Ni 0.9091 0.9730 0.8919 0.8055 0.71340.6150 Ti 0.0909 0.0000 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.00000.0803 0.1657 0.2568 0.3542 Sm 0.0000 0.0270 0.0279 0.0288 0.0297 0.0308m 49.8 50.8 49.5 49.7 50.3 49.7 3 Ni 0.8163 0.8743 0.9412 0.8516 0.75570.6527 Ti 0.1837 0.0984 0.0000 0.0000 0.0000 0.0000 Zr 0.0000 0.00000.0000 0.0876 0.1814 0.2820 Sm 0.0000 0.0273 0.0588 0.0608 0.0630 0.0653m 49.5 50.4 49.7 50.1 50.3 49.9 4 Ni 0.7216 0.7735 0.8333 0.9032 0.80320.6954 Ti 0.2784 0.1989 0.1071 0.0000 0.0000 0.0000 Zr 0.0000 0.00000.0000 0.0000 0.0964 0.2003 Sm 0.0000 0.0276 0.0595 0.0968 0.1004 0.1043m 49.5 49.5 50.7 — 49.5 50.7 5 Ni 0.6250 0.6704 0.7229 0.7843 0.85710.7440 Ti 0.3750 0.3017 0.2169 0.1176 0.0000 0.0000 Zr 0.0000 0.00000.0000 0.0000 0.0000 0.1071 Sm 0.0000 0.0279 0.0602 0.0980 0.1429 0.1488m 50.6 49.6 49.8 48.6 50.7 48.8 6 Ni 0.5263 0.5650 0.6098 0.6623 0.72460.8000 Ti 0.4737 0.4068 0.3293 0.2384 0.1304 0.0000 Zr 0.0000 0.00000.0000 0.0000 0.0000 0.0000 Sm 0.0000 0.0282 0.0610 0.0993 0.1449 0.2000m 50.4 49.5 50.4 51.0 49.9 49.3

Example 10 ODHE Over NiTiSmX (X═Cs, Mg, Ca, Sb, Bi, V, Nb, Ta) andNiTiNbTaSm Oxide Catalysts (#116297/16506/16650)

Catalyst compositions comprising various NiTiSniX oxides, where X is Cs,Mg, Ca, Sb, Bi, T or Nlb were prepared in small (˜100 mg) quantities byprecipitation substantially as described in connection with Example 1.Table 10A summarizes the composition and amounts of the various catalystcompositions.

In an initial screening (calcination at 300° C., 8 hours, screening infixed bed parallel reactor at 300° C. with flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, as described), ethaneconversion values for the NiTiSmCs oxide compositions ranged from 13.8%(with ethylene selectivity of 76.5%) to 18.2% (with ethylene selectivityof 83.7%), and ethylene selectivity values ranged from 76.5% (withethane conversion of 13.8%) to 84.7% (with ethane conversion of 18.0%).Ethane conversion values for the NiTiSmMg oxide compositions ranged from15.9% (with ethylene selectivity of 85.2%) to 19.1% (with ethyleneselectivity of 85.4%), and ethylene selectivity values ranged from 83.9%(with ethane conversion of 17.3%) to 85.7% (with ethane conversion of17.3%). Ethane conversion values for the NiTiSmCa oxide compositionsranged from 14.5% (with ethylene selectivity of 78.7%) to 19.1% (withethylene selectivity of 83.5%), and ethylene selectivity values rangedfrom 78.7% (with ethane conversion of 14.5%) to 85.6% (with ethaneconversion of 15.9%). Ethane conversion values for the NiTiSmSb oxidecompositions ranged from 15.6% (with ethylene selectivity of 83.2%) to18.7% (with ethylene selectivity of 83.1%), and ethylene selectivityvalues ranged from 81.5% (with ethane conversion of 16.3%) to 85.1%(with ethane conversion of 17.9%). Ethane conversion values for theNiTiSmBi oxide compositions ranged from 11.1% (with ethylene selectivityof 60.1%) to 17.9% (with ethylene selectivity of 86.1%), and ethyleneselectivity values ranged from 59.0% (with ethane conversion of 11.3%)to 86.1% (with ethane conversion of 17.9%). Ethane conversion values forthe NiTiSmV oxide compositions ranged from 12.1% (with ethyleneselectivity of 76.5%) to 16.9% (with ethylene selectivity of 83.5%), andethylene selectivity values ranged from 74.8% (with ethane conversion of13.3%) to 83.5% (with ethane conversion of 16.9%). Ethane conversion (C)and ethylene selectivity (S) values for the NiTiSmNb oxide compositionsranged from 16.0% C, 80.4% S to 20.0% C, 85.5% S. Ethane conversionvalues for the NiTiSmTa oxide compositions ranged from 6.1% (withethylene selectivity of 72.7%) to 20.0% (with ethylene selectivity of85.5%), and ethylene selectivity values ranged from 72.7% with ethaneconversion of 6.1%) to 87.3% (with ethane conversion of 18.8%).

In a second screening in the fixed bed parallel reactor at 300° C. withdifferent flowrates (ethane:nitrogen:oxygen of 0.42:0.23:0.061 sccm),ethane conversion values for the NiTiSmCs oxide compositions ranged from15.0% (with ethylene selectivity of 80.4%) to 19.3% (with ethyleneselectivity of 88.4%), and ethylene selectivity values ranged from 80.4%(with ethane conversion of 15.0%) to 90.2% (with ethane conversion of18.3%). Ethane conversion values for the NiTiSmMg oxide compositionsranged from 17.3% (with ethylene selectivity of 89.4%) to 20.0% (withethylene selectivity of 88.5%), and ethylene selectivity values rangedfrom 87.3% (with ethane conversion of 18.3%) to 90.2% (with ethaneconversion of 17.9%). Ethane conversion values for the NiTiSmCa oxidecompositions ranged from 15.2% (with ethylene selectivity of 83.9%) to20.0% (with ethylene selectivity of 86.9%), and ethylene selectivityvalues ranged from 83.9% (with ethane conversion of 15.2%) to 89.9%(with ethane conversion of 17.9%). Ethane conversion values for theNiTiSmSb oxide compositions ranged from 15.9% (with ethylene selectivityof 86.9%) to 19.1% (with ethylene selectivity of 88.1%), and ethyleneselectivity values ranged from 85.2% (with ethane conversion of 17.3%)to 88.1% (with ethane conversion of 19.1%). Ethane conversion values forthe NiTiSmBi oxide compositions ranged from 13.2% (with ethyleneselectivity of 81.4%) to 19.9% (with ethylene selectivity of 85.8%), andethylene selectivity values ranged from 78.1% (with ethane conversion of14.1%) to 85.9% (with ethane conversion of 16.7%). Ethane conversionvalues for the NiTiSmV oxide compositions ranged from 14.5% (withethylene selectivity of 81.8%) to 17.9% (with ethylene selectivity of84.3%), and ethylene selectivity values ranged from 78.7% (with ethaneconversion of 15.1%) to 86.1% (with ethane conversion of 17.1%). Ethaneconversion (C) and ethylene selectivity (S) values for the NiTiSmNboxide compositions ranged from 17.3% C, 84.7% S to 19.6% C, 89.1% S.Ethane conversion (C) and ethylene selectivity (S) values for theNiTiSmNb oxide compositions ranged from 7.3% C, 72.8% S to 20.3% C,89.5% S.

TABLE 10A Catalyst composition (mole fraction) of NiTiSmX oxidecatalysts, where X is Cs, Mg, Ca, Sb, Bi, V or Nb, and sample mass, “m”(mg) used in parallel fixed bed reactor screen. Row Col 1 2 3 4 5 6 1 Ni0.6667 0.6593 0.6522 0.6452 0.6383 0.6316 Ti 0.3056 0.3022 0.2989 0.29570.2926 0.2895 Sm 0.0278 0.0275 0.0272 0.0269 0.0266 0.0263 Cs 0.00000.0110 0.0217 0.0323 0.0426 0.0526 m 48.8 49.5 50.3 50.2 50.2 50.5 2 Ni0.6621 0.6557 0.6495 0.6434 0.6375 0.6316 Ti 0.3034 0.3005 0.2977 0.29490.2922 0.2895 Mg 0.0069 0.0164 0.0257 0.0349 0.0438 0.0526 Sm 0.02760.0273 0.0271 0.0268 0.0266 0.0263 m 49.4 50.2 50.6 49.5 49.3 50.3 3 Ni0.6621 0.6557 0.6495 0.6434 0.6375 0.6316 Ti 0.3034 0.3005 0.2977 0.29490.2922 0.2895 Ca 0.0069 0.0164 0.0257 0.0349 0.0438 0.0526 Sm 0.02760.0273 0.0271 0.0268 0.0266 0.0263 m 49.7 49.2 50.8 50.5 50.2 50.6 4 Ni0.6624 0.6560 0.6498 0.6437 0.6377 0.6318 Ti 0.3036 0.3007 0.2978 0.29500.2923 0.2896 Sm 0.0276 0.0273 0.0271 0.0268 0.0266 0.0263 Sb 0.00650.0160 0.0253 0.0345 0.0435 0.0524 m 50.7 49.6 49.6 49.8 50.6 49.7 5 Ni0.6621 0.6557 0.6495 0.6434 0.6375 0.6316 Ti 0.3034 0.3005 0.2977 0.29490.2922 0.2895 Sm 0.0276 0.0273 0.0271 0.0268 0.0266 0.0263 Bi 0.00690.0164 0.0257 0.0349 0.0438 0.0526 m 49.5 50.5 49.8 49.5 51.3 49.5 6 Ni0.6621 0.6557 0.6495 0.6434 0.6375 0.6316 Ti 0.3034 0.3005 0.2977 0.29490.2922 0.2895 Sm 0.0276 0.0273 0.0271 0.0268 0.0266 0.0263 V 0.00690.0164 0.0257 0.0349 0.0438 0.0526 m 50.3 45.0 49.5 49.7 50.6 50.0 7 Ni0.6554 0.6360 0.6177 0.6005 0.5842 0.5687 Nb 0.0169 0.0460 0.0734 0.09930.1237 0.1469 Ti 0.3004 0.2915 0.2831 0.2752 0.2677 0.2607 Sm 0.02730.0265 0.0257 0.0250 0.0243 0.0237 m 49.5 50.3 49.5 49.4 50.5 49.6 8 Ni0.6541 0.6350 0.6170 0.6000 0.5839 0.5686 Ti 0.2998 0.2911 0.2828 0.27500.2676 0.2606 Ta 0.0188 0.0475 0.0745 0.1000 0.1242 0.1471 Sm 0.02730.0265 0.0257 0.0250 0.0243 0.0237 m 49.2 50.2 49.9 51.1 50.1 50.0

In another independent experiment, a NiTiNbTaSm oxide catalyst havingthe composition Ni_(0.68)Ti_(0.10)Nb_(0.10)Ta_(0.10)Sm_(0.02)O_(x) wasprepared and screened in the parallel fixed bed reactor. Briefly, thefollowing aqueous stock solutions were added to a glass vial in theamounts indicated: nickel nitrate ([Ni]=1.0M, 2.0 ml), titanium oxalate([Ti]=0.713M with oxalic acid 0.18M), niobium oxalate ([Nb]=0.569M withoxalic acid 0.173M, 0.517 ml), tantalum oxalate ([Ta]=0.650M with oxalicacid 0.14M, 0.452 ml) and samarium nitrate ([Sm]=0.506M, 0.116 ml).Tetramethylammonium hydroxide ([NMe₄OH]=1.44M, 3.06 ml) was injectedinto the catalyst precursor composition, resulting in precipitation. Toinsure adequate mixing, distilled water (3.0 ml) was also injected intothe mixture. The resulting precipitate mixture was settled at 25° C. for2 hours, and then centrifuged at 3000 rpm. The solution was decanted andthe solids were dried under vacuum at 60° C. in a vacuum oven. The driedmaterials were then calcined by heating to 320° C. at 5° C./min andmaintaining at 320° C. for 8 hours in air. After subsequent cooling to25° C., solid NiTiNbTaSm oxide (0.296 g) was obtained and 48.7 mgthereof was tested for ethane oxidative dehydrogenation in the parallelfixed bed reactor at 300° C. with an ethane:oxygen flow of 0.42:0.083sccm. Ethane conversion (C) and ethylene selectivity (S) were determinedto be 22.3% C and 85.2% S.

Example 11 ODHE Over NiTiSn/NiZrSn Oxide Catalysts (#16470/16505)

Catalyst compositions comprising various NiTiSn and NiZrSn oxides wereprepared and screened substantially as described in connection withExample 1,%with tin acetate ([Sn=0.249 M]) aqueous stock solution. Thevarious catalyst compositions and amounts are summarized in Table 11A(NiTiSn oxides) and Table 11B (NiZrSn oxides).

For the NiTiSn oxide catalysts, in an initial screening (calcination at300° C., 8 hours, screening in fixed bed parallel reactor at 300° C.with flowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, asdescribed), ethane conversion values for the NiTiSn oxide compositionsranged from 11.1% (with ethylene selectivity of 79.4%) to 19.2% (withethylene selectivity of 85.4%), and ethylene selectivity values rangedfrom 79.2% (with ethane conversion of 14.8%) to 86.1% (with ethaneconversion of 18.2%).

In a second screening of these catalysts in the fixed bed parallelreactor at 300° C. with different flowrates (ethane:nitrogen:oxygen of1.04:0.21:0.055 sccm), ethane conversion values for the NiTiSn oxidecompositions ranged from 8.5% (with ethylene selectivity of 90.8%) to10.2% (with ethylene selectivity of 94.0%), and ethylene selectivityvalues ranged from 90.8% (with ethane conversion of 8.5%) to 94.3% (withethane conversion of 9.9%).

In a third screening of these catalysts in the fixed bed parallelreactor at a different temperature, 275° C., and with differentflowrates (ethane:nitrogen:oxygen of 1.05:0.082:0.022), ethaneconversion values for the NiTiSn oxide compositions ranged from 3.5%(with ethylene selectivity of 86.0%) to 8.5% (with ethylene selectivityof 92.8%), and ethylene selectivity values ranged from 85.4% (withethane conversion of 4.4%) to 93.4% (with ethane conversion of 7.9%).

For the NiZrSn oxide catalysts, in an initial screening (calcination at300° C., 8 hours, screening in fixed bed parallel reactor at 300° C.with flowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, asdescribed), ethane conversion values for the NiZrSn oxide compositionsranged from 15.0% (with ethylene selectivity of 77.3%) to 17.8% (withethylene selectivity of 80.9%), and ethylene selectivity values rangedfrom 77.2% (with ethane conversion of 15.6%) to 81.9% (with ethaneconversion of 17.1%).

In a second screening of these catalysts in the fixed bed parallelreactor at 300° C. with different flowrates (ethane:nitrogen:oxygen of1.04:1.34:0.22 sccm), ethane conversion values for the NiZrSn oxidecompositions ranged from 8.2% (with ethylene selectivity of 87.8%) to9.3% (with ethylene selectivity of 90.9%), and ethylene selectivityvalues ranged from 87.8% (with ethane conversion of 8.2%) to 91.8% (withethane conversion of 9.1%).

In a third screening of these catalysts in the fixed bed parallelreactor at a different temperature, 275° C., and with differentflowrates (ethane:nitrogen:oxygen of 1.04:0.021:0.055), ethaneconversion values for the NiZrSn oxide compositions ranged from 5.8%(with ethylene selectivity of 83.3%) to 7.8% (with ethylene selectivityof 88.3% and ethylene selectivity values ranged from 82.2% (with ethaneconversion of 6.3%) to 88.9% (with ethane conversion of 7.6%).

TABLE 11A Catalyst composition (mole fraction) of NiTiSn oxide catalystsand sample mass (mg) used in parallel fixed bed reactor screen. RowColumn 1 2 3 4 5 6 1 Ni 0.875 Ti 0.125 Sn 0.000 mass 51.7 (mg) 2 Ni0.862 0.787 Ti 0.129 0.213 Sn 0.009 0.000 mass 54.2 48.2 (mg) 3 Ni 0.8470.771 0.708 Ti 0.134 0.220 0.292 Sn 0.019 0.008 0.000 mass 53.9 46.146.6 (mg) 4 Ni 0.832 0.755 0.691 0.637 Ti 0.139 0.228 0.301 0.363 Sn0.029 0.018 0.008 0.000 mass 53.0 50.0 51.0 48.0 (mg) 5 Ni 0.815 0.7360.672 0.618 0.572 Ti 0.145 0.236 0.311 0.374 0.428 Sn 0.040 0.027 0.0170.008 0.000 mass 45.0 52.3 50.0 52.8 46.1 (mg) 6 Ni 0.796 0.717 0.6520.598 0.552 0.513 Ti 0.151 0.245 0.322 0.386 0.441 0.487 Sn 0.052 0.0380.026 0.016 0.007 0.000 mass 49.5 46.4 52.0 44.9 50.6 49.1 (mg)

TABLE 11B Catalyst composition (mole fractions) of NiZrSn oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen. Row Column 1 2 3 4 5 6 1 Ni 0.914 Zr 0.086 Sn 0.000 mass 45.8(mg) 2 Ni 0.901 0.849 Zr 0.089 0.151 Sn 0.009 0.000 mass 52.9 51.2 (mg)3 Ni 0.888 0.834 0.786 Zr 0.093 0.157 0.214 Sn 0.020 0.009 0.000 mass50.9 50.6 47.6 (mg) 4 Ni 0.873 0.818 0.770 0.727 Zr 0.097 0.163 0.2210.273 Sn 0.031 0.019 0.009 0.000 mass 55.6 54.4 53.1 51.2 (mg) 5 Ni0.857 0.801 0.752 0.708 0.670 Zr 0.101 0.169 0.230 0.283 0.330 Sn 0.0430.030 0.019 0.009 0.000 mass 55.1 51.8 49.2 53.8 49.2 (mg) 6 Ni 0.8390.782 0.732 0.688 0.649 0.615 Zr 0.105 0.176 0.239 0.293 0.342 0.385 Sn0.056 0.042 0.029 0.018 0.009 0.000 mass 51.8 51.3 45.5 59.0 50.7 50.6(mg)

Example 12 ODHE Over Bulk NiTa, NiNb, NiNbTa (Various Forms), NiNbTaCe,NiTa(Ce, Dy), and NiNb(Ce, Sb, Dy, Sm) Oxide Catalysts

In a first group of experiments, various NiTa, NiTaNb, NiNbCe and NiNbSboxide catalysts were prepared in large, bulk quantities (˜20 g), and ˜50mg thereof was screened in the parallel fixed bed reactor at 300° C.with ethane:nitrogen:oxygen flow of 0.42:0.54:0.058 sccm, as follows.Catalyst compositions, sample mass, and resulting ethane conversion andethylene selectivity are summarized in Table 12A.

(#120S7) Ni_(0.83)Ta_(0.17): Aqueous solution of nickel nitrate (1.0M,167.0 ml) was mixed with tantalum oxalate (0.66M in water with 0.26Moxalic acid, 53.0 ml). To the stirring mixture of nickel nitrate andtantalum oxalate, tetramethylammonium hydroxide aqueous solution (1.42M,210.0 ml) was added to give precipitation. The water in the mixture wasremoved by freeze-drying, and the resulting solid was then calcinedunder an atmosphere of air at the heating rate of 1° C./min to thetemperature of 120° C., dwelled at 120 C for 2 hrs, at the heating rateof 1° C./min to 180° C., dwelled at 180° C. for 2 hrs, the heating rateof 2° C./min to 400° C. and dwelled at 400° C. for 8 hrs, and thencooled to 25° C. Gray solid NiTa oxide (18.0 g) were obtained and 50.0mg thereof was tested in the fixed bed parallel reactor for ethaneoxidative dehydrogenation under the aforementioned conditions.

(#12277) Ni_(0.62)Ta_(0.19)Nb_(0.19): Aqueous solution of nickel nitrate(1.0M, 153.0 ml), tantalum oxalate aqueous solution (0.66M in water with0.26M oxalic acid, 73.0 ml), and niobium oxalate aqueous solution (0.62Min water wvith 0.35M oxalic acid, 76.0 ml) were mixed in a 2 L beaker.While the solution was vigorously stirred by a mechanical stir, ammoniumcarbonate aqueous solution (1.62M, 285.0 ml) was added in a controlledmanner so that the foam was formed slowly to give precipitation. Themixture was transferred to containers, which was centrifuged at 4000 rpmfor 15 minutes. The solution was decanted and solid materials werefurther dried at 60° C. under reduced pressure for 5 hours. Theresulting solid materials were calcined under an atmosphere of air at 3°C./min to 350° C. and dwelled at 350° C. for 8 hours, and then cooled to25° C. Dark gray solid NiTaNb oxide (19.0 g) was obtained, and 50.0 mgthereof was tested in the parallel fixed bed reactor for ethaneoxidative dehydrogenation under the aforementioned conditions.

(#12442) Ni_(0.62)Ta_(0.10)Nb_(0.28): Aqueous solution of nickel nitrate(1.0M, 80.0 ml), tantalum oxalate aqueous solution (0.66M in water with0.26M oxalic acid, 19.0 ml), and niobium oxalate aqueous solution (0.62Min water with 0.35M oxalic acid, 57.0 ml) were mixed in a 2 L beaker.While the solution was vigorously stirred by a mechanical stir, ammoniumcarbonate aqueous solution (1.62M, 143.0 ml) was added in a controlledmanner so that the foam was formed slowly to give precipitation. Themixture was transferred to containers, which was centrifuged at 4000 rpmfor 15 minutes. The solution was decanted and solid materials werefurther dried at 60° C. under reduced pressure for 5 hours. Theresulting solid materials were calcined under an atmosphere of air at 2°C./min to 300° C. and dwelled at 300° C. for 8 hours, and then cooled to25° C. Dark gray solid NiTaNb oxide (12.0 g) was obtained and about 50mg thereof was tested in the parallel fixed bed reactor for ethaneoxidative dehydrogenation under the aforementioned conditions.

(#14560) Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x): Aqueous solution of nickelnitrate (1.0M, 150.0 ml), niobium oxalate aqueous solution (0.58M inwater with 0.14M oxalic acid, 131.0 ml), and cerium nitrate (1.0M, 4.6ml) were mixed in a 2 L beaker. While the solution was vigorouslystirred by a mechanical stir, ammonium carbonate aqueous solution(1.62M, 214.7 ml) was added in a controlled manner so that the foam wasformed slowly to give precipitation. The mixture was transferred tocontainers, which was centrifuged at 4000 rpm for 15 minutes. Thesolution was decanted and solid materials were further dried at 60° C.under reduced pressure for 5 hours. The resulting solid materials werecalcined under an atmosphere of air at 2° C./min to 300° C. and dwelledat 300° C. for 8 hours, and then cooled to 25° C. Dark gray solid NiNbCeoxide (20.94 g) was obtained and 45.8 mg thereof was tested in theparallel fixed bed reactor for ethane oxidative dehydrogenation underthe aforementioned conditions.

(#14620) Ni_(0.65)Nb_(0.23)Ce_(0.02)O_(x): NiNbCe oxide (10.41 g)prepared as described above in connection with library #14560 wasfurther calcined to 400° C. at 2° C./min and dwelled at 400° C. for 8hrs under an atmosphere of air. Solid NiNbCe oxide (10.19 g) wasobtained, and 49.2 mg thereof was tested in the parallel fixed bedreactor for ethane oxidative dehydrogenation under the aforementionedconditions.

(#14587) Ni_(0.71)Nb_(0.27)Sb_(0.2)O_(x): Aqueous solution of nickelnitrate (1.0M, 150.0 ml), niobium oxalate aqueous solution (0.58M inwater with 0.14M oxalic acid, 98.3 ml), and antimony acetate aqueoussolution (0.234M with oxalic acid 1.27M, 18.1 ml) were mixed in a 2 Lbeaker. While the solution was vigorously stirred by a mechanical stir,ammonium carbonate aqueous solution (1.62M, 228.4 ml) was added in acontrolled manner so that the foam was formed slowly to giveprecipitation. The mixture was transferred to containers, which wascentrifuged at 4000 rpm for 15 minutes. The solution was decanted andsolid materials were further dried at 60° C. under reduced pressure for5 hours. The resulting solid materials were calcined under an atmosphereof air at 2° C./min to 300° C. and dwelled at 300° C. for 8 hours, andthen cooled to 25° C. Dark gray solid NiNbSb oxide (18.75 g) wasobtained and 54.8 mg thereof was tested in the parallel fixed bedreactor for ethane oxidative dehydrogenation under the aforementionedconditions.

(#14624) Ni_(0.71)Nb_(0.27)Sb_(0.02)O_(x): NiNbSb oxide (8.86 g)prepared as described above in connection with library #14587 wasfurther calcined to 400° C. at 2° C./min and dwelled at 400° C. for 8hrs under an atmosphere of air. Solid NiNbSb oxide (8.60 g) wasobtained, and 54.1 mg thereof was tested in the parallel fixed bedreactor for ethane oxidative dehydrogenation under the aforementionedconditions.

TABLE 12A Catalyst composition (mole fractions), sample mass (mg) andperformance characteristics of various NiTa, NiTaNb, NiNbCe and NiNbSboxide catalysts. Test conditions: 300° C. with ethane:nitrogen:oxygenflow of 0.42:0.54:0.088 sccm. Library # Composition Mass (mg) ConversionSelectivity 12087 Ni_(0.83)Ta_(0.17)O_(x) 50.0 11.1% 85.0% 12277Ni_(0.62)Ta_(0.19)Nb_(0.19)O_(x) 50.0 10.0% 85.4% 12442Ni_(0.62)Ta_(0.10)Nb_(0.28)O_(x) 50.0 17.0% 83.7% 14560Ni_(0.65)Nb_(0.33)Ce_(0.02) 45.8 18.6% 83.0% O_(x) 14620Ni_(0.65)Nb_(0.33)Ce_(0.02) 49.2 13.8% 82.0% O_(x) 14587Ni_(0.71)Nb_(0.27)Sb_(0.02)O_(x) 54.8 20.2% 81.6% 14624Ni_(0.71)Nb_(0.27)Sb_(0.02)O_(x) 54.1 14.4% 82.5%

In another group of experiments, various NiTa, NiTaCe, NiTaDy, NiNbTaCe,NiNbDy, NiNb and titania supported NiNbSm oxide catalysts were preparedin large, bulk quantities (˜20 g), and various amounts thereof werescreened in the parallel fixed bed reactor at 300° C. withethane:nitrogen:oxygen flow of 0.42:0.08:0.022 sccm, as follows.Catalyst compositions, sample mass, and resulting ethane conversion andethylene selectivity are summarized in Table 12B.

(#15891) Ni_(0.86)Ta_(0.14)O_(x): Aqueous solution of nickel nitrate(1.0M, 150.0 ml), and tantalum oxalate aqueous solution (0.69M in waterwith 0.9M oxalic acid, 35.0 ml) were mixed in a 1 L beaker. While thesolution was vigorously stirred by a mechanical stir, ammonium carbonateaqueous solution (1.62M, 150.0 ml) was added in a controlled manner sothat the foam was formed slowly to give precipitation. The mixture wastransferred to containers, which was centrifuged at 3000 rpm for 15minutes. The solution was decanted and solid materials were furtherdried at 60° C. under reduced pressure for 5 hours. The resulting solidmaterials were calcined under an atmosphere of air at 2° C./min to 320°C. and dwelled at 320° C. for 8 hours, and then cooled to 25° C. Darkgray solid NiTa oxide (15.0 g) was obtained and 45.6 mg thereof wastested in the parallel fixed bed reactor for ethane oxidativedehydrogenation under the aforementioned reaction conditions.

(#15915) Ni_(0.65)Ta_(0.31)Ce_(0.04)O_(x): Aqueous solution of nickelnitrate (1.0M, 120.0 ml), tantalum oxalate aqueous solution (0.69M inwater with 0.19M oxalic acid, 83.0 ml), and cerium nitrate aqueoussolution (0.50M, 15.0 ml) were mixed in a 1 L beaker. While the solutionwas vigorously stirred by a mechanical stir, ammonium carbonate aqueoussolution (1.62M, 174.0 ml) was added in a controlled manner so that thefoam was formed slowly to give precipitation. The mixture wastransferred to containers, which was centrifuged at 3000 rpm for 15minutes. The solution was decanted and solid materials were furtherdried at 60° C. under reduced pressure for 5 hours. The resulting solidmaterials were calcined under an atmosphere of air at 2° C./min to 320°C. and dwelled at 320° C. for 8 hours, and then cooled to 25° C. Darkgray solid NiTaCe oxide (21.9 g) was obtained and 51.3 mg thereof wastested in the parallel fixed bed reactor for ethane oxidativedehydrogenation under the aforementioned reaction conditions.

(#15916) Ni_(0.73)Ta_(0.24)Dy_(0.03)O_(x): Aqueous solution of nickelnitrate (1.0M, 150.0 ml), tantalum oxalate aqueous solution (0.51M inwater with 0.67M oxalic acid, 97.0 ml), and dysprosium acetate aqueoussolution (0.294M, 21.0 ml) were mixed in a 1 L beaker. While thesolution was vigorously stirred by a mechanical stir, ammonium carbonateaqueous solution (1.62M, 269.0 ml) was added in a controlled manner sothat the foam was formed slowly to give precipitation. The mixture wastransferred to containers, which was centrifuged at 3000 rpm for 15minutes. The solution was decanted and solid materials were furtherdried at 60° C. under reduced pressure for 5 hours. The resulting solidmaterials were calcined under an atmosphere of air at 2° C./min to 320°C. and dwelled at 320° C. for 8 hours, and then cooled to 25° C. Darkgray solid NiTaDy oxide (21.9 g) was obtained and 50.0 mg thereof wastested in the parallel fixed bed reactor for ethane oxidativedehydrogenation under the aforementioned reaction conditions.

(#15922) Ni_(0.74)Nb_(0.08)Ta_(0.17)Cc_(0.01)O_(x): Aqueous solution ofnickel nitrate (1.0M, 150.0 ml), tantalum oxalate aqueous solution(0.51M in water with 0.67M oxalic acid, 68.0 ml), niobium oxalateaqueous solution (0.62M in water with 0.21M oxalic acid, 26.0 ml), andcerium nitrate aqueous solution (0.50M, 4.0 ml) were mixed in a 1 Lbeaker. While the solution was vigorously stirred by a mechanical stir,ammonium carbonate aqueous solution (1.62M, 235.0 ml) was added in acontrolled manner so that the foam was formed slowly to giveprecipitation. The mixture was transferred to containers, which wascentrifuged at 3000 rpm for 15 minutes. The solution was decanted andsolid materials were further dried at 60° C. under reduced pressure for5 hours. The resulting solid materials were calcined under an atmosphereof air at 2° C./min to 320° C. and dwelled at 320° C. for 8 hours, andthen cooled to 25° C. Dark gray solid NiNbTaCe oxide (20.7 g) wasobtained and 68.5 mg thereof was tested in the parallel fixed bedreactor for ethane oxidative dehydrogenation under the aforementionedreaction conditions.

(#15927) Ni_(0.68)Nb_(0.25)Dy_(0.07)O_(x): Aqueous solution of nickelnitrate (1.0M, 150.0 ml), niobium oxalate aqueous solution (0.62M inwater with 0.21M oxalic acid, 89.0 ml), and dysprosium acetate aqueoussolution (0.294M, 53.0 ml) were mixed in a 1 L beaker. While thesolution was vigorously stirred by a mechanical stir, ammonium carbonateaqueous solution (1.62M, 206.0 ml) was added in a controlled manner sothat the foam was formed slowly to give precipitation. The mixture wastransferred to containers, which was centrifuged at 3000 rpm for 15minutes. The solution was decanted and solid materials were furtherdried at 60° C. under reduced pressure for 5 hours. The resulting solidmaterials were calcined under an atmosphere of air at 2° C./min to 320°C. and dwelled at 320° C. for 8 hours, and then cooled to 25° C. Darkgray solid NiNbDy oxide (19.4 g) was obtained and 47.0 mg thereof testedin the parallel fixed bed reactor for ethane oxidative dehydrogenationunder the aforementioned reaction conditions.

(#15931) Ni_(0.82)Nb_(0.18)O_(x): Aqueous solution of nickel nitrate(1.0M, 150.0 ml), and niobium oxalate aqueous solution (0.62M in waterwith 0.21M oxalic acid, 53.0 ml) were mixed in a 1 L beaker. While thesolution was vigorously stirred by a mechanical stir, ammonium carbonateaqueous solution (1.62M, 164.0 ml) was added in a controlled manner sothat the foam was formed slowly to give precipitation. The mixture wastransferred to containers, which was centrifuged at 3000 rpm for 15minutes. The solution was decanted and solid materials were furtherdried at 60° C. under reduced pressure for 5 hours. The resulting solidmaterials were calcined under an atmosphere of air at 2° C./min to 320°C. and dwelled at 320° C. for 8 hours, and then cooled to 25° C. Darkgray solid NiNb oxide (14.1 g) was obtained and 47.3 mg thereof wastested in the parallel fixed bed reactor for ethane oxidativedehydrogenation under the aforementioned reaction conditions.

(#15944) Ni_(0.63)Nb_(0.34)SM_(0.03)O_(x)/TiO2: TiO₂ support in pelletform was dried at 100° C. for over 8 hrs. After cooling to 25° C., TiO₂support was impregnated with the mixed metal nitrate or oxalatesolution. Catalyst loading was about 6% by weight, relative to totalweight of the catalyst. After centrifugation, the solid materialsobtained were dried at 60° C. under vacuum, and then calcined to 300° C.at 2° C./min and dwelled at 300° C. for 8 hrs. The NiNbSm oxide wasobtained and ˜143 mg thereof was tested in the parallel fixed bedreactor for ethane oxidative dehydrogenation under the aforementionedreaction conditions.

TABLE 12B Catalyst composition (mole fractions), sample mass (mg) andperformance characteristics of various NiTa, NiTaCe, NiTaDy, NiNbTaCe,NiNbDy, NiNb and titania supported NiNbSm oxide catalysts. Testconditions: 300° C. with ethane:nitrogen:oxygen flow of 0.42:0.08:0.022sccm. Library # Composition Mass (mg) Conversion Selectivity 15891Ni_(0.86)Ta_(0.14)O_(x) 45.6 mg 10.3% 91.3% 15915Ni_(0.65)Ta_(0.31)Ce_(0.04)O_(x) 51.3 mg 10.5% 93.2% 15916Ni_(0.73)Ta_(0.24)Dy_(0.03)O_(x) 50.0 mg 10.2% 93.3% 15922Ni_(0.74)Nb_(0.08)Ta_(0.17) 68.5 mg 10.8% 94.3% Ce_(0.01)O_(x) 15927Ni_(0.68)Nb_(0.25)Dy_(0.07)O_(x) 47.0 mg 10.5% 91.8% 15931Ni_(0.82)Nb_(0.18)O_(x) 47.3 mg 10.2% 93.1% 15944Ni_(0.63)Nb_(0.34)Sm_(0.03)O_(x)/ 142.8 mg  8.6% 93.0% TiO2* *Catalystloading on the support is about 6% by weight.

In a third group of experiments, NiNbTa oxide catalysts of a singlecomposition were prepared in large, bulk quantities (˜20 g) and invarious physical forms, and various amounts thereof were screened in theparallel fixed bed reactor at 300° C. with ethane:nitrogen:oxygen flowof 0.42:0.54:0.088 sccm, as follows. The catalyst composition, physicalform, sample mass and resulting ethane conversion and ethyleneselectivity are summarized in Table 12C.

(#16116) Ni_(0.63)Nb_(0.19)Ta_(0.18)O_(x): Aqueous solution of nickelnitrate (1.0M, 150.0 ml), niobium oxalate aqueous solution (0.62M inwater with 0.21M oxalic acid, 73.0 ml), and tantalum oxalate aqueoussolution (0.51M in water with 0.67M oxalic acid, 84.0 ml), were mixed ina 1 L beaker. While the solution was vigorously stirred by a mechanicalstir, tetramethylammonium hydroxide aqueous solution (1.28M, 390.0 ml)was added quickly to give precipitation. Additional water (100 ml) wasadded and mixed with the resulting mixture. The mixture was transferredto containers, which was centrifuged at 3000 rpm for 15 minutes. Thesolution was decanted and solid materials were further dried at 60° C.under reduced pressure for 5 hours. The resulting solid materials werecalcined under an atmosphere of air at 2° C./min to 320° C. and dwelledat 320° C. for 8 hours, and then cooled to 25° C. Dark gray solid NiNbTaoxide (15.9 g) was obtained and 50.0 mg thereof was tested, as formed inbulk, in the parallel fixed bed reactor for ethane oxidativedehydrogenation under the aforementioned reaction conditions.

For comparison of the effect of physical form of the catalyst, a portionof the NiNbTa oxide bulk catalyst prepared as above was pressed andbroken into small pieces (but not ground) to fit into the reactionvessels of the parallel fixed bed reactor, and 73.9 mg thereof wastested, in pressed and broken form, in the parallel fixed bed reactorfor ethane oxidative dehydrogenation under the aforementioned reactionconditions. Additionally, another portion of the NiNbTa oxide bulkcatalyst prepared as described above was pressed and ground, and 68.0 mgthereof was tested, in pressed and ground form, in the parallel fixedbed reactor for ethane oxidative dehydrogenation under theaforementioned reaction conditions.

TABLE 12C Physical form, sample mass (mg) and performancecharacteristics of Ni_(0.63)Nb_(0.19)Ta_(0.18)O_(x) catalysts (#16116).Test conditions: 300° C. with ethane:nitrogen:oxygen flow of0.42:0.54:0.088 sccm. Composition Form Mass (mg) Conversion SelectivityNi_(0.63)Nb_(0.19)Ta_(0.18)O_(x) bulk 50.0 18.4 84.1Ni_(0.63)Nb_(0.19)Ta_(0.18)O_(x) P*, B* 73.9 20.1 85.0Ni_(0.63)Nb_(0.19)Ta_(0.18)O_(x) P*, G* 68.0 19.1 84.6 P* = pressed; B*= broken (not ground); G* = ground.

Example 13 ODHE Over NiNbSmX Oxide Catalyst, X═Cs, Mg, Ca, Sb, Bi, V,Ti, Ta (#16298/16507)

Catalyst compositions comprising various NiNbSmX oxides, where X is Cs,Mg, Ca, Sb, Bi, V, Ti or Ta were prepared in bulk (˜20 g) quantities byprecipitation substantially as described in connection with Example 1.Nickel nitrate ([Ni]=1.0 M), niobium oxalate ([Nb]=0.569 M), samariumnitrate ([Sm]=0.506 M), cesium nitrate ([Cs]=1.00 M), magnesium nitrate([Mg]=1.00 M), calcium nitrate ([Ca]=1.00 M), antimony acetate([Sb]=0.234 M), bismuth citrate ([Bi]=0.293 M), vanadium oxalate([V]=1.00 M), titanium oxalate ([Ti]=0.713 M), and tantalum oxalate([Ta]=0.650 M) aqueous stock solutions were used. Table 13A summarizesthe composition and amounts of the various catalyst compositions.

In an initial screening (calcination at 300° C., 8 hours, screening infixed bed parallel reactor at 300° C. with flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, as described), ethaneconversion (C) and ethylene selectivity (S) values for the NiNbSmCsoxide compositions ranged from 16.3% C, 78.5% S to 19.2% C, 84.9% S.Ethane conversion values for the NiNbSmMg oxide conmpositions rangedfrom 17.5% (with ethylene selectivity of 83.1%) to 19.4% (with ethyleneselectivity of 84.8%), and ethylene selectivity values ranged from 83.1%(with ethane conversion of 17.5%) to 84.9% (with ethane conversion of18.7%). Ethane conversion (C) and ethylene selectivity (S) values forthe NiNbSmCa oxide compositions ranged from 18.2% C, 83.3% S to 20.0% C,84.5% S. Ethane conversion (C) and ethylene selectivity (S) values forthe NiNbSmSb oxide compositions ranged from 16.3% C, 80.3% S to 19.0% C,86.4% S. Ethane conversion (C) and ethylene selectivity (S) values forthe NiNbSmBi oxide compositions ranged from 17.1% C, 79.4% S to 19.5% C,84.6% S. Ethane conversion values for the NiNbSmV oxide compositionsranged from 13.8% (with ethylene selectivity of 80.3%) to 17.7% (withethylene selectivity of 84.3%), and ethylene selectivity values rangedfrom 79.9% (with ethane conversion of 14.0%) to 84.3% (with ethaneconversion of 17.7%). Ethane conversion (C) and ethylene selectivity (S)values for the NiNbSmTi oxide compositions ranged from 17.6% C, 82.8% Sto 19.1% C, 84.9% S. Ethane conversion values for the NiNbSmTa oxidecompositions ranged from 17.3% (with ethylene selectivity of 83.6%) to20.2% (with ethylene selectivity of 84.3%), and ethylene selectivityvalues ranged from 83.4% (with ethane conversion of 17.8%) to 84.9%(with ethane conversion of 18.2%).

In a second screening in the fixed bed parallel reactor at 300° C. withdifferent flowrates (ethane:nitrogen:oxygen of 0.42:0.23:0.061 sccm),ethane conversion (C) and ethylene selectivity (S) values for theNiNbSmCs oxide compositions ranged from 17.0% C, 83.0% S to 19.8% C,88.7% S. Ethane conversion values for the NiNbSmMg oxide compositionsranged from 16.0% (with ethylene selectivity of 88.3%) to 18.9% (withethylene selectivity of 88.2%), and ethylene selectivity values rangedfrom 86.4% (with ethane conversion of 18.1%) to 88.3% (with ethaneconversion of 18.8%). Ethane conversion values for the NiNbSmCa oxidecompositions ranged from 18.2% (with ethylene selectivity of 86.3%) to19.8% (with ethylene selectivity of 87.6%), and ethylene selectivityvalues ranged from 86.3% (with ethane conversion of 18.2%) to 87.8%(with ethane conversion of 18.7%). Ethane conversion values for theNiNbSmSb oxide compositions ranged from 17.0% (with ethylene selectivityof 84.2%) to 19.5% (with ethylene selectivity of 89.3%), and ethyleneselectivity values ranged from 84.2% (with ethane conversion of 17.0%)to 89.5% (with ethane conversion of 19.4%). Ethane conversion values forthe NiNbSmBi oxide compositions ranged from 17.1% (with ethyleneselectivity of 82.4%) to 19.8% (with ethylene selectivity of 87.7%), andethylene selectivity values ranged from 82.4% (with ethane conversion of17.1%) to 88.7% (with ethane conversion of 18.5%). Ethane conversionvalues for the NiNbSmV oxide compositions ranged from 14.0% (withethylene selectivity of 76.7%) to 18.7% (with ethylene selectivity of86.8%), and ethylene selectivity values ranged from 76.7% (with ethaneconversion of 14.0%) to 88.2% (with ethane conversion of 17.8%). Ethaneconversion values for the NiNbSmTi oxide compositions ranged from 17.7%(with ethylene selectivity of 87.3%) to 19.4% (with ethylene selectivityof 88.0%), and ethylene selectivity values ranged from 86.3% (withethane conversion of 18.6%) to 88.2% (with ethane conversion of 19.1%).Ethane conversion values for the NiNbSmTa oxide compositions ranged from18.1% (with ethylene selectivity of 86.8%) to 19.0% (with ethyleneselectivity of 87.7%), and ethylene selectivity values ranged from 86.1%(with ethane conversion of 18.5%) to 87.8% (with ethane conversion of18.1%).

TABLE 13A Catalyst composition (mole fraction) of NiNbSmX OxideCatalysts, where X is Cs, Mg, Ca, Sb, Bi, V, Ti or Ta, and sample mass,“m” (mg) used in parallel fixed bed reactor screen. Row Col 1 2 3 4 5 61 Ni 0.7528 0.7439 0.7352 0.7267 0.7184 0.7103 Nb 0.2164 0.2138 0.21130.2089 0.2065 0.2042 Sm 0.0308 0.0304 0.0301 0.0297 0.0294 0.0291 Cs0.0000 0.0118 0.0234 0.0347 0.0457 0.0565 m 49.4 49.9 49.3 50.6 50.650.8 2 Ni 0.7464 0.7389 0.7315 0.7243 0.7172 0.7103 Nb 0.2146 0.21240.2103 0.2082 0.2062 0.2042 Mg 0.0085 0.0185 0.0283 0.0379 0.0473 0.0565Sm 0.0305 0.0302 0.0299 0.0296 0.0293 0.0291 m 49.6 49.8 49.3 49.7 49.950.4 3 Ni 0.7464 0.7389 0.7315 0.7243 0.7172 0.7103 Nb 0.2146 0.21240.2103 0.2082 0.2062 0.2042 Ca 0.0085 0.0185 0.0283 0.0379 0.0473 0.0565Sm 0.0305 0.0302 0.0299 0.0296 0.0293 0.0291 m 49.3 50.2 50.7 49.9 49.250.1 4 Ni 0.7468 0.7392 0.7317 0.7244 0.7172 0.7102 Nb 0.2147 0.21250.2103 0.2082 0.2062 0.2041 Sm 0.0306 0.0302 0.0299 0.0296 0.0293 0.0291Sb 0.0079 0.0181 0.0280 0.0378 0.0473 0.0567 m 50.8 49.8 50.2 50.9 50.849.9 5 Ni 0.7464 0.7389 0.7315 0.7243 0.7172 0.7103 Nb 0.2146 0.21240.2103 0.2082 0.2062 0.2042 Sm 0.0305 0.0302 0.0299 0.0296 0.0293 0.0291Bi 0.0085 0.0185 0.0283 0.0379 0.0473 0.0565 m 50.9 50.6 50.2 49.4 49.349.9 6 Ni 0.7464 0.7389 0.7315 0.7243 0.7172 0.7103 Nb 0.2146 0.21240.2103 0.2082 0.2062 0.2042 Sm 0.0305 0.0302 0.0299 0.0296 0.0293 0.0291V 0.0085 0.0185 0.0283 0.0379 0.0473 0.0565 m 50.4 49.8 50.8 51.0 49.449.6 7 Ni 0.7401 0.7156 0.6926 0.6711 0.6508 0.6317 Nb 0.2128 0.20570.1991 0.1929 0.1871 0.1816 Ti 0.0168 0.0494 0.0800 0.1086 0.1355 0.1608Sm 0.0303 0.0293 0.0283 0.0275 0.0266 0.0258 m 49.7 49.7 50.6 49.5 50.550.3 8 Ni 0.7389 0.7163 0.6950 0.6750 0.6561 0.6383 Nb 0.2124 0.20590.1998 0.1940 0.1886 0.1835 Ta 0.0185 0.0485 0.0767 0.1033 0.1284 0.1521Sm 0.0302 0.0293 0.0284 0.0276 0.0268 0.0261 m 49.4 49.5 49.9 50.4 50.750.0

Example 14 ODHE Over NiNbCu Oxide Catalysts (#16360/16511)

Catalyst compositions comprising various NiNbCu oxides were prepared insmall (˜100 mg) quantities by precipitation substantially as describedin connection with Example 1, using copper nitrate ([Cu]=1.00 M) aqueousstock solution. Table 14A summarizes the composition and amounts of thevarious catalyst compositions.

In an initial screening (calcination at 300° C., 8 hours, screening infixed bed parallel reactor at 300° C. with flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, as described), ethaneconversion (C) and ethylene selectivity (S) values for the NiNbCu oxidecompositions ranged from 7.2% C, 47.9% S to 16.9% C, 79.7% S.

In a second screening in the fixed bed parallel reactor at 300° C. withdifferent flowrates (ethane:nitrogen:oxygen of 0.42:0.23:0.061 sccm),ethane conversion values for the NiNbCu oxide compositions ranged from7.4% (with ethylene selectivity of 48.2%) to 16.9% (with ethyleneselectivity of 83.2%), and ethylene selectivity values ranged from 48.2%(with ethane conversion of 7.4%) to 83.6% (with ethane conversion of16.2%).

In a third screening in the fixed bed parallel reactor at 300° C. withdifferent flowrates (ethane:nitrogen:oxygen of 0.42:0.082:0.022 sccm),ethane conversion (C) and ethylene selectivity (S) values for the NiNbCuoxide compositions ranged from 4.1% C, 54.6% S to 10.2% C, 91.4% S.

TABLE 14A Catalyst compositions (mole fraction) of NiNbCu OxideCatalysts and sample mass, “m” (mg) used in parallel fixed bed reactorscreen. Row Col 1 2 3 4 5 6 1 Ni 0.8574 0.7923 0.7263 0.6594 0.59150.5226 Nb 0.1426 0.2077 0.2737 0.3406 0.4085 0.4774 Cu 0.0000 0.00000.0000 0.0000 0.0000 0.0000 m 49.8 50.7 50.7 49.3 50.2 49.7 2 Ni 0.85300.7882 0.7226 0.6559 0.5884 0.5198 Nb 0.1419 0.2066 0.2723 0.3388 0.40640.4749 Cu 0.0051 0.0052 0.0052 0.0052 0.0053 0.0053 m 50.9 49.5 50.550.8 50.7 49.4 3 Ni 0.8487 0.7842 0.7188 0.6525 0.5853 0.5171 Nb 0.14120.2056 0.2709 0.3371 0.4042 0.4724 Cu 0.0102 0.0103 0.0103 0.0104 0.01050.0105 m 49.2 50.0 50.3 49.6 49.8 50.7 4 Ni 0.8444 0.7802 0.7151 0.64920.5822 0.5144 Nb 0.1404 0.2045 0.2695 0.3353 0.4021 0.4699 Cu 0.01520.0153 0.0154 0.0155 0.0156 0.0157 m 50.6 49.4 50.0 50.9 50.0 50.7 5 Ni0.8401 0.7762 0.7115 0.6458 0.5792 0.5117 Nb 0.1397 0.2035 0.2681 0.33360.4000 0.4674 Cu 0.0202 0.0203 0.0204 0.0206 0.0207 0.0209 m 50.8 50.450.3 50.0 49.9 50.4 6 Ni 0.8359 0.7723 0.7079 0.6425 0.5762 0.5090 Nb0.1390 0.2024 0.2667 0.3319 0.3980 0.4650 Cu 0.0251 0.0252 0.0254 0.02560.0258 0.0260 m 50.0 50.4 50.6 49.8 49.9 50.4

Example 15 ODHE Over NiNbCo Oxide Catalysts (#16365/16512)

Catalyst compositions comprising various NiNbCo oxides were prepared insmall (˜100 mg) quantities by precipitation substantially as describedin connection with Example 1, using cobalt nitrate ([Co]=1.00 M) aqueousstock solution. Table 15A summarizes the composition and amounts of thevarious catalyst compositions.

In an initial screening (calcination at 300° C., 8 hours, screening infixed bed parallel reactor at 300° C. with flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, as described), ethaneconversion values for the NiNbCo oxide compositions ranged from 7.6%(with ethylene selectivity of 80.7%) to 20.6% (with ethylene selectivityof 85.9%), and ethylene selectivity values ranged from 73.1% (withethane conversion of 14.2%) to 85.9% (with ethane conversion of 20.6%).

In a second screening in the fixed bed parallel reactor at 300° C. withdifferent flowrates (ethane:nitrogen:oxygen of 0.42:0.23:0.061 sccm),ethane conversion values for the NiNbCo oxide compositions ranged from8.8% (with ethylene selectivity of 81.9%) to 19.9% (with ethyleneselectivity of 88.0%), and ethylene selectivity values ranged from 77.6%(with ethane conversion of 14.6%) to 88.0% (with ethane conversion of19.9%).

In a third screening in the fixed bed parallel reactor at 300° C. withdifferent flowrates (ethane:nitrogen:oxygen of 0.42:0.082:0.022 sccm),ethane conversion values for the NiNbCo oxide compositions ranged from7.7% (with ethylene selectivity of 89.4%) to 11.8% (with ethyleneselectivity of 93.2%), and ethylene selectivity values ranged from 83.0%(with ethane conversion of 8.7%) to 92.9% (with ethane conversion of11.7%).

TABLE 15A Catalyst compositions (mole fraction) of NiNbCo oxidecatalysts and sample mass, “m” (mg) used in parallel fixed bed reactorscreen. Row Col 1 2 3 4 5 6 1 Ni 0.8552 0.7903 0.7245 0.6577 0.59000.5212 Nb 0.1422 0.2072 0.2730 0.3397 0.4075 0.4762 Co 0.0025 0.00250.0026 0.0026 0.0026 0.0026 m 50.5 49.9 50.9 49.6 50.4 49.4 2 Ni 0.85150.7868 0.7213 0.6547 0.5873 0.5189 Nb 0.1416 0.2062 0.2718 0.3382 0.40560.4740 Co 0.0069 0.0069 0.0070 0.0070 0.0071 0.0071 m 50.4 50.1 50.849.8 49.4 49.1 3 Ni 0.8478 0.7834 0.7181 0.6518 0.5847 0.5165 Nb 0.14100.2053 0.2706 0.3367 0.4038 0.4718 Co 0.0112 0.0113 0.0114 0.0115 0.01150.0116 m 50.9 50.0 50.0 50.5 49.3 49.6 4 Ni 0.8441 0.7799 0.7149 0.64890.5820 0.5142 Nb 0.1404 0.2044 0.2694 0.3352 0.4020 0.4697 Co 0.01550.0156 0.0157 0.0158 0.0160 0.0161 m 50.3 50.0 49.5 50.9 49.7 49.4 5 Ni0.8404 0.7765 0.7118 0.6461 0.5795 0.5119 Nb 0.1398 0.2035 0.2682 0.33370.4002 0.4676 Co 0.0198 0.0199 0.0201 0.0202 0.0203 0.0205 m 49.3 50.849.9 50.7 50.4 50.3

Example 16 ODHE Over NiNbCr Oxide Catalysts (#16373/16513)

Catalyst compositions comprising various NiNbCr oxides were prepared inbulk (˜20 g) quantities by precipitation substantially as described inconnection with Example 1, using chromium nitrate ([Cr]=1.00 M) aqueousstock solution. Table 16A summarizes the composition and amounts of thevarious catalyst compositions.

In an initial screening (calcination at 300° C., 8 hours, screening infixed bed parallel reactor at 300° C. with flowrates ofethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm, as described), ethaneconversion values for the NiNbCr oxide compositions ranged from 11.7%(with ethylene selectivity of 71.9%) to 18.1% (with ethylene selectivityof 82.7%, and ethylene selectivity values ranged from 71.5% (with ethaneconversion of 13.1%) to 83.8% (with ethane conversion of 17.7%).

In a second screening in the fixed bed parallel reactor at 300° C. withdifferent flowrates (ethane:nitrogen:oxygen of 0.42:0.23:0.061 sccm),ethane conversion values for the NiNbCr oxide compositions ranged from14.1% (with ethylene selectivity of 80.5%) to 18.6% (with ethyleneselectivity of 86.7%), and ethylene selectivity values ranged from 78.8%(with ethane conversion of 15.1%) to 87.0% (with ethane conversion of18.3%).

In a third screening in the fixed bed parallel reactor at 300° C. withdifferent flowrates (ethane:nitrogen:oxygen of 0.42:0.082:0.022 sccm),ethane conversion values for the NiNbCr oxide compositions ranged from8.6% (with ethylene selectivity of 85.0%) to 11.2% (with ethyleneselectivity of 90.0%), and ethylene selectivity values ranged from 85.0%(with ethane conversion of 8.6%) to 91.5% (with ethane conversion of10.9%).

TABLE 16A Catalyst compositions (mole fraction) of NiNbCr OxideCatalysts and sample mass, “m” (mg) used in parallel fixed bed reactorscreen. Row Col 1 2 3 4 5 6 1 Ni 0.8552 0.7903 0.7245 0.6577 0.59000.5212 Nb 0.1422 0.2072 0.2730 0.3397 0.4075 0.4762 Cr 0.0025 0.00250.0026 0.0026 0.0026 0.0026 m 50.8 50.0 49.8 49.7 50.0 49.4 2 Ni 0.85040.7858 0.7203 0.6539 0.5865 0.5182 Nb 0.1414 0.2060 0.2714 0.3378 0.40510.4734 Cr 0.0081 0.0082 0.0082 0.0083 0.0084 0.0084 m 50.7 50.6 50.450.7 50.9 50.0 3 Ni 0.8457 0.7814 0.7162 0.6502 0.5832 0.5152 Nb 0.14070.2048 0.2699 0.3359 0.4028 0.4706 Cr 0.0137 0.0138 0.0139 0.0140 0.01410.0142 m 50.3 49.5 50.1 49.7 50.4 50.4 4 Ni 0.8410 0.7770 0.7122 0.64650.5798 0.5122 Nb 0.1399 0.2037 0.2684 0.3339 0.4005 0.4679 Cr 0.01920.0193 0.0194 0.0196 0.0197 0.0198 m 50.6 50.0 49.9 49.9 49.5 50.8 5 Ni0.8363 0.7727 0.7082 0.6428 0.5765 0.5093 Nb 0.1391 0.2025 0.2669 0.33210.3982 0.4652 Cr 0.0246 0.0248 0.0249 0.0251 0.0253 0.0255 m 50.7 49.950.7 50.5 50.2 49.3

Example 17 ODHE Over NiNbGd/NiTaGd Oxide Catalysts (#13899)

Catalyst compositions comprising various NiNbGd and NiTaGd oxides wereprepared in small (˜100 mg) quantities by precipitation substantially asdescribed in connection with Example 1, using gadolinium nitrate([Gd]=1.00 M) aqueous stock solution, and calcining to 320° C. at 5°C./min and maintaining at 320° C. for 8 hours in air. The compositionsand amounts of the various catalyst compositions are shown in Table 17A(NiNbGd) and Table 17B (NiTaGd).

The NiNbGd oxide catalysts were screened in the fixed bed parallelreactor for oxidative ethane dehydrogenation at 300° C. with flowratesof ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm. Ethane conversionvalues for the NiNbGd oxide compositions ranged from 4.9% (with ethyleneselectivity of 48.2%) to 20.3% (with ethylene selectivity of 83.2%), andethylene selectivity values ranged from 45.6% (with ethane conversion of7.2%) to 83.9% (with ethane conversion of 17.6%).

The NiTaGd oxide catalysts were likewise screened in the fixed bedparallel for oxidative ethane dehydrogenation reactor (300° C.;flowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm). Ethaneconversion values for the NiTaGd oxide compositions ranged from 8.0%(with ethylene selectivity of 53.4%) to 19.0% (with ethylene selectivityof 84.7%), and ethylene selectivity values ranged from 51.7% (withethane conversion of 8.3%) to 84.9% (with ethane conversion of 16.2%).

Additional screens of the NiNbGd oxide catalysts were effected atdifferent temperatures (250° C.; ethane:nitrogen:oxygen flow of0.42:0.54:0.088 sccm) and, in separate experiments, at differentflowrates (300° C.; ethane:nitrogen:oxygen flow of 1.05:1.35:0.22 sccm)(data not shown).

TABLE 17A Catalyst compositions (mole fractions) of NiNbGd oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen. Row Column 1 2 3 4 5 6 1 Ni 0.896 Nb 0.104 Gd 0.000 mass 47.3(mg) 2 Ni 0.815 0.820 Nb 0.099 0.180 Gd 0.086 0.000 mass 50.8 54.7 (mg)3 Ni 0.740 0.745 0.749 Nb 0.095 0.173 0.251 Gd 0.164 0.083 0.000 mass52.2 49.8 46.9 (mg) 4 Ni 0.671 0.675 0.679 0.683 Nb 0.092 0.166 0.2410.317 Gd 0.237 0.159 0.080 0.000 mass 49.6 54.9 49.7 52.8 (mg) 5 Ni0.608 0.611 0.615 0.618 0.622 Nb 0.088 0.160 0.232 0.305 0.378 Gd 0.3040.229 0.154 0.077 0.000 mass 55.2 54.0 50.5 49.7 47.0 (mg) 6 Ni 0.5490.552 0.555 0.558 0.561 0.564 Nb 0.085 0.154 0.223 0.293 0.364 0.436 Gd0.366 0.294 0.222 0.149 0.075 0.000 mass 50.7 50.5 50.7 51.4 52.9 45.0(mg)

TABLE 17B Catalyst compositions (mole fractions) of NiTaGd oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen. Row Column 1 2 3 4 5 6 1 Ni 0.879 Ta 0.121 Gd 0.000 Mass 55.5(mg) 2 Ni 0.800 0.793 Ta 0.116 0.207 Gd 0.084 0.000 Mass 50.9 51.4 (mg)3 Ni 0.727 0.721 0.715 Ta 0.111 0.199 0.285 Gd 0.162 0.080 0.000 Mass55.9 51.3 46.7 (mg) 4 Ni 0.660 0.655 0.649 0.644 Ta 0.107 0.191 0.2740.356 Gd 0.233 0.154 0.076 0.000 Mass 52.7 53.0 53.6 51.7 (mg) 5 Ni0.598 0.593 0.589 0.584 0.580 Ta 0.103 0.184 0.264 0.343 0.420 Gd 0.2990.222 0.147 0.073 0.000 Mass 55.1 47.5 54.6 50.8 45.5 (mg) 6 Ni 0.5400.536 0.532 0.528 0.525 0.521 Ta 0.099 0.178 0.255 0.331 0.405 0.479 Gd0.360 0.286 0.213 0.141 0.070 0.000 Mass 49.6 51.8 51.8 52.8 55.6 48.6(mg)

Example 18 ODHE Over NiNbBi and NiTaBi Oxide Catalysts

Catalyst compositions comprising various NiNbBi and NiTaBi oxides wereprepared in small (˜100 mg) quantities by precipitation substantially asdescribed in connection with Example 1, using bismuth citrate([Bi]=0.293 M) aqueous stock solution. The compositions and amounts ofthe various catalyst compositions are showvn in Table 18A (NiNbBi) andTable 18B (NiTaBi).

The NiNbBi oxide catalysts were initially screened in the fixed bedparallel reactor for oxidative ethane dehydrogenation at 300° C. withflowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm. Ethaneconversion values for the NiNbBi oxide compositions ranged from 13.1%(with ethylene selectivity of 72.9%) to 19.8% (with ethylene selectivityof 84.2%), and ethylene selectivity values ranged from 72.9% (withethane conversion of 13.1%) to 84.9% (with ethane conversion of 17.5%)

The NiNbBi catalysts were subsequently recalcined to 400° C. (5° C./minto 400° C.; dwell at 400° C. for 8 hours), and then screened in theparallel fixed bed reactor for ethane dehydrogenation under the samereaction conditions as the initial screen (300° C.;ethane:nitrogen:oxygen flow of 0.42:0.54:0.088 sccm). Ethane conversionvalues for the NiNbBi oxide compositions ranged from 9.9% (with ethyleneselectivity of 85.6%) to 14.1% (with ethylene selectivity of 85.2%), andethylene selectivity values ranged from 74.6% (with ethane conversion of12.7%) to 86.3% (with ethane conversion of 13.3%)

The recalcined NiNbBi catalysts were screened again in the parallelfixed bed reactor at different flowrates screen (300° C.;ethane:nitrogen:oxygen flow of 0.42:0.081:0.022 sccm). Ethane conversionvalues for the NiNbBi oxide compositions ranged from 9.5% (with ethyleneselectivity of 93.0%) to 10.9% (with ethylene selectivity of 93.4%), andethylene selectivity values ranged from 89.8% (with ethane conversion of10.2%) to 93.8% (with ethane conversion of 10.6%).

The NiTaBi oxide catalysts were likewise initially screened in the fixedbed parallel reactor for oxidative ethane dehydrogenation reactor (300°C.; flowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm). Ethaneconversion values for the NiTaBi oxide compositions ranged from 13.6%(with ethylene selectivity of 82.5%) to 19.1% (with ethylene selectivityof 84.8%), and ethylene selectivity values ranged from 78.9% (withethane conversion of 13.7%) to 84.8% (with ethane conversion of 19.1%)

The NiTaBi catalysts were subsequently recalcined to 400° C. (5° C./minto 400° C.; dwell at 400° C. for 8 hours), and then screened in theparallel fixed bed reactor for ethane dehydrogenation under the samereaction conditions as the initial screen (300° C.;ethane:nitrogen:oxygen flow of 0.42:0.54:0.088 sccm). Ethane conversionvalues for the NiTaBi oxide compositions ranged from 9.4% (with ethyleneselectivity of 77.1%) to 13.5% (with ethylene selectivity of 84.3%), andethylene selectivity values ranged from 74.6% (with ethane conversion of10.4%) to 86.9% (with ethane conversion of 11.1%).

The recalcined NiTaBi catalysts were screened again in the parallelfixed bed reactor at different flowrates screen (300° C.;ethane:nitrogen:oxygen flow of 0.42:0.081:0.022 sccm). Ethane conversion(C) and ethylene selectivity (S) values for the NiTaBi oxidecompositions ranged from 8.6% C, 87.8% S to 11.0% C, 93.6% S.

TABLE 18A Catalyst compositions (mole fractions) of NiNbBi oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen. Row Column 1 2 3 4 5 6 1 Ni 0.890 Nb 0.110 Bi 0.000 Mass 53.9(mg) 2 Ni 0.879 0.810 Nb 0.115 0.190 Bi 0.007 0.000 Mass 50.7 53.4 (mg)3 Ni 0.867 0.796 0.736 Nb 0.119 0.197 0.264 Bi 0.014 0.006 0.000 mass53.0 49.2 52.9 (mg) 4 Ni 0.853 0.781 0.721 0.668 Nb 0.125 0.205 0.2730.332 Bi 0.022 0.013 0.006 0.000 mass 56.1 53.6 54.7 51.4 (mg) 5 Ni0.839 0.765 0.704 0.651 0.606 Nb 0.130 0.214 0.284 0.343 0.394 Bi 0.0310.021 0.013 0.006 0.000 mass 49.3 45.5 53.2 52.0 46.0 (mg) 6 Ni 0.8240.748 0.685 0.632 0.587 0.547 Nb 0.136 0.223 0.295 0.355 0.407 0.453 Bi0.040 0.029 0.020 0.012 0.006 0.000 mass 49.7 51.1 53.9 47.0 48.2 46.9(mg)

TABLE 18B Catalyst compositions (mole fractions) of NiTaBi oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen. Row Column 1 2 3 4 5 6 1 Ni 0.906 Ta 0.094 Bi 0.000 mass 55.3(mg) 2 Ni 0.891 0.835 Ta 0.098 0.165 Bi 0.011 0.000 mass 46.3 54.6 (mg)3 Ni 0.876 0.819 0.769 Ta 0.101 0.170 0.231 Bi 0.023 0.011 0.000 mass48.2 53.8 55.8 (mg) 4 Ni 0.859 0.801 0.751 0.706 Ta 0.105 0.176 0.2390.294 Bi 0.036 0.022 0.010 0.000 mass 54.5 50.7 52.6 50.9 (mg) 5 Ni0.841 0.783 0.731 0.687 0.647 Ta 0.109 0.183 0.247 0.303 0.353 Bi 0.0490.034 0.021 0.010 0.000 mass 51.9 54.2 50.0 54.0 51.1 (mg) 6 Ni 0.8220.762 0.711 0.665 0.626 0.591 Ta 0.114 0.190 0.256 0.314 0.364 0.409 Bi0.064 0.048 0.033 0.021 0.010 0.000 mass 52.5 48.6 51.5 48.6 51.0 50.7(mg)

Example 19 ODHE Over NiNbSb/NiTaSb Oxide Catalysts

Catalyst compositions comprising various NiNbSb and NiTaSb oxides wereprepared in small (˜100 mg) quantities by precipitation substantially asdescribed in connection with Example 1, using antimony acetate([Sb]=0.234 M) aqueous stock solution. The compositions and amounts ofthe various catalyst compositions are shown in Table 19A (NiNbSb) andTable 19B (NiTaSb).

The NiNbSb oxide catalysts were initially screened in the fixed bedparallel reactor for oxidative ethane dehydrogenation at 300° C. withflowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm. Ethaneconversion (C) and ethylene selectivity (S) values for the NiNbSb oxidecompositions ranged from 14.8% C, 67.6% S to 20.9% C, 84.4% S.

The NiNbSb catalysts were screened again in the parallel fixed bedreactor at different flowrates screen (300° C., ethane:nitrogen:oxygenflow of 1.04:1.34:0.22 sccm). Ethane conversion values for the NiNbSboxide compositions ranged from 11.8% (with ethylene selectivity of81.1%) to 18.4% (with ethylene selectivity of 84.0%), and ethyleneselectivity values ranged from 77.0% (with ethane conversion of 12.6%)to 84.6% (with ethane conversion of 12.7%).

The NiTaSb oxide catalysts were likewise initially screened in the fixedbed parallel reactor for oxidative ethane dehydrogenation reactor (300°C.; flowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm). Ethaneconversion values for the NiTaSb oxide compositions ranged from 14.5%(with ethylene selectivity of 72.2%) to 18.7% (with ethylene selectivityof 82.1%), and ethylene selectivity values ranged from 72.2% (withethane conversion of 14.5%) to 83.5% (with ethane conversion of 18.4%).

The NiTaSb catalysts were screened again in the parallel fixed bedreactor at different flowrates screen (300° C.; ethane:nitrogen:oxygenflow of 1.04:1.34:0.22 sccm). Ethane conversion values for the NiTaSboxide compositions ranged from 10.0% (with ethylene selectivity of69.5%) to 14.2% (with ethylene selectivity of 80.2%), and ethyleneselectivity values ranged from 69.5% (with ethane conversion of 10.0%)to 83.1% (wvitlh ethane conversion of 13.4%).

TABLE 19A Catalyst compositions (mole fractions) of NiNbSb oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen. Row Column 1 2 3 4 5 6 1 Ni 0.890 Nb 0.110 Sb 0.000 Mass 51.6(mg) 2 Ni 0.879 0.814 Nb 0.115 0.186 Sb 0.006 0.000 Mass 45.0 49.8 (mg)3 Ni 0.867 0.801 0.744 Nb 0.119 0.193 0.256 Sb 0.014 0.006 0.000 Mass46.1 44.5 51.3 (mg) 4 Ni 0.854 0.786 0.728 0.678 Nb 0.125 0.201 0.2660.322 Sb 0.021 0.013 0.006 0.000 Mass 51.0 53.3 46.1 48.3 (mg) 5 Ni0.840 0.771 0.712 0.661 0.617 Nb 0.130 0.209 0.276 0.333 0.383 Sb 0.0290.020 0.012 0.006 0.000 Mass 52.7 48.9 52.9 48.0 50.9 (mg) 6 Ni 0.8250.754 0.694 0.643 0.599 0.560 Nb 0.136 0.218 0.287 0.345 0.396 0.440 Sb0.039 0.028 0.019 0.012 0.006 0.000 Mass 49.7 45.9 46.6 47.3 51.4 54.8(mg)

TABLE 19B Catalyst compositions (mole fractions) of NiTaSb oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen. Row Column 1 2 3 4 5 6 1 Ni 0.879 Ta 0.121 Sb 0.000 Mass 51.8(mg) 2 Ni 0.868 0.788 Ta 0.126 0.212 Sb 0.006 0.000 Mass 50.3 52.2 (mg)3 Ni 0.855 0.774 0.707 Ta 0.131 0.220 0.293 Sb 0.013 0.006 0.000 Mass50.0 52.4 52.0 (mg) 4 Ni 0.842 0.759 0.691 0.634 Ta 0.137 0.228 0.3030.366 Sb 0.021 0.013 0.006 0.000 Mass 51.4 51.1 50.2 50.4 (mg) 5 Ni0.828 0.743 0.674 0.617 0.569 Ta 0.143 0.237 0.314 0.378 0.431 Sb 0.0290.020 0.012 0.005 0.000 Mass 51.7 52.2 50.3 52.1 51.8 (mg) 6 Ni 0.8120.726 0.656 0.598 0.550 0.509 Ta 0.149 0.247 0.326 0.391 0.445 0.491 Sb0.038 0.027 0.018 0.011 0.005 0.000 Mass 50.0 50.3 50.5 51.6 51.5 50.3(mg)

Example 20 ODHE Over NiNbSn/NiTaSn Oxide Catalysts (#16467/#16469)

Catalyst compositions comprising various NiNbSn and NiTaSn oxides wereprepared in small (˜100 mg) quantities by precipitation substantially asdescribed in connection with Example 1, using tin acetate ([Sn]=0.249 M)aqueous stock solution. The compositions and amounts of the variouscatalyst compositions are shown in Table 20A (NiNbSn) and Table 20B(NiTaSn).

The NiNbSn oxide catalysts were initially screened in the fixed bedparallel reactor for oxidative ethane dehydrogenation at 300° C. withflowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm. Ethaneconversion values for the NiNbSn oxide compositions ranged from 15.1%(with ethylene selectivity of 82.0%) to 19.4% (with ethylene selectivityof 84.8%), and ethylene selectivity values ranged from 82.0% (withethane conversion of 15.1%) to 85.8% (with ethane conversion of 19.2%).

The NiNbSn catalysts were screened again in the parallel fixed bedreactor at different flowrates screen (300° C.; ethane:nitrogen:oxygenflow of 1.04:1.34:0.22 sccm). Ethane conversion values for the NiNbSnoxide compositions ranged from 8.8% (with ethylene selectivity of 80.4%)to 13.3% (with ethylene selectivity of 84.4%), and ethylene selectivityvalues ranged from 80.4% (with ethane conversion of 8.8%) to 85.9% (withethane conversion of 12.8%).

In a third screen, the NiNbSn catalysts were screened in the parallelfixed bed reactor at different flowrates screen (300° C.;ethane:nitrogen:oxygen flow of 1.04:0.21:0.055 sccm). Ethane conversionvalues for the NiNbSn oxide compositions ranged from 8.4% (with ethyleneselectivity of 91.8%) to 10.0% (with ethylene selectivity of 93.5%), andethylene selectivity values ranged from 89.1% (with ethane conversion of9.8%) to 93.5% (with ethane conversion of 10.0%).

In a fourth screen, the NiNbSn catalysts were screened in the parallelfixed bed reactor at different flowrates screen (300° C.;ethane:nitrogen:oxygen flow of 0.42:0.082:0.022 sccm). Ethane conversion(C) and ethylene selectivity (S) values for the NiNbSn oxidecompositions ranged from 8.7% C, 89.8% S to 11.5% C, 93.8% S.

The NiTaSn oxide catalysts were likewise initially screened in the fixedbed parallel for oxidative ethane dehydrogenation reactor (300° C.;flowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm). Ethaneconversion values for the NiTaSn oxide compositions ranged from 16.6%(with ethylene selectivity of 84.6%) to 20.3% (with ethylene selectivityof 85.6%), and ethylene selectivity values ranged from 84.1% (withethane conversion of 18.3%) to 85.7% (with ethane conversion of 19.7%).

The NiTaSn catalysts were screened again in the parallel fixed bedreactor at different flowrates screen (300° C.; ethane:nitrogen:oxygenflow of 1.04:1.34:0.22 sccm). Ethane conversion values for the NiTaSnoxide compositions ranged from 9.0% (with ethylene selectivity of 89.7%)to 11.0% (with ethylene selectivity of 94.1%), and ethylene selectivityvalues ranged from 88.7% (with ethane conversion of 10.1%) to 94.2%(with ethane conversion of 10.0%).

In a third screen, the NiTaSn catalysts were screened in the parallelfixed bed reactor at a different temperature and at different flowratesscreen (275° C.; ethane:nitrogen:oxygen flow of 1.04:0.21:0.055 sccm).Ethane conversion values for the NiTaSn oxide compositions ranged from6.9% (with ethylene selectivity of 91.8%) to 8.8% (with ethyleneselectivity of 93.6%), and ethylene selectivity values ranged from 91.3%(with ethane conversion of 7.7%) to 94.1% (with ethane conversion of7.7%).

TABLE 20A Catalyst compositions (mole fractions) of NiNbSn oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen. Row Column 1 2 3 4 5 6 1 Ni 0.898 Nb 0.102 Sn 0.000 Mass 47.0(mg) 2 Ni 0.885 0.823 Nb 0.106 0.177 Sn 0.009 0.000 Mass 53.6 50.4 (mg)3 Ni 0.871 0.807 0.753 Nb 0.110 0.184 0.247 Sn 0.019 0.009 0.000 Mass48.3 47.0 55.0 (mg) 4 Ni 0.856 0.791 0.735 0.687 Nb 0.115 0.191 0.2560.313 Sn 0.030 0.018 0.009 0.000 Mass 52.0 54.1 52.7 51.5 (mg) 5 Ni0.839 0.773 0.717 0.668 0.626 Nb 0.119 0.198 0.265 0.323 0.374 Sn 0.0410.029 0.018 0.008 0.000 Mass 49.2 52.1 48.0 51.5 47.8 (mg) 6 Ni 0.8210.754 0.697 0.648 0.606 0.569 Nb 0.125 0.206 0.275 0.335 0.386 0.431 Sn0.054 0.040 0.028 0.017 0.008 0.000 Mass 54.5 50.2 46.4 51.9 53.2 47.8(mg)

TABLE 20B Catalyst compositions (mole fractions) of NiTaSn oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen. Row Column 1 2 3 4 5 6 1 Ni 0.885 Ta 0.115 Sn 0.000 Mass 52.6(mg) 2 Ni 0.872 0.802 Ta 0.119 0.198 Sn 0.009 0.000 mass 52.3 53.1 (mg)3 Ni 0.857 0.787 0.727 Ta 0.124 0.205 0.273 Sn 0.019 0.009 0.000 mass54.1 54.5 49.0 (mg) 4 Ni 0.842 0.770 0.710 0.658 Ta 0.129 0.212 0.2820.342 Sn 0.029 0.018 0.008 0.000 mass 53.0 51.7 53.9 47.7 (mg) 5 Ni0.825 0.752 0.691 0.639 0.594 Ta 0.134 0.220 0.292 0.353 0.406 Sn 0.0410.028 0.017 0.008 0.000 mass 52.7 53.7 50.9 53.7 50.3 (mg) 6 Ni 0.8070.733 0.671 0.619 0.574 0.536 Ta 0.140 0.229 0.302 0.365 0.418 0.464 Sn0.053 0.039 0.027 0.016 0.008 0.000 mass 52.0 50.4 52.7 50.9 53.0 51.8(mg)

Example 21 ODHE Over NiTaCe/NiNbCe/NiNbTaCe Oxide Catalysts(#12314/#12080/#12380/#11285)

NiTaCe catalyst compositions were prepared in bulk by precipitationsubstantially as described in connection with Example 1, using ceriumnitrate ([Ce]=1.00 M) aqueous stock solution, and calcining by heatingto 350° C. at 2° C./min and maintaining at 350° C. for 8 hours in air.The compositions and amounts of the various NiTaCe catalyst compositionsare shonvn in Table 21A.

The NiTaCe oxide catalysts wvere screened in the fixed bed parallelreactor for oxidative ethane dehydrogenation at 300° C. with flowratesof ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm. Ethane conversionvalues for the NiTaCe oxide compositions ranged from 0.1% (with ethyleneselectivity of 59.4%) to 18.1% (with ethylene selectivtiy of 84.7%), andethylene selectivity values ranged from 31.9% (with ethane conversion of2.8%) to 85.4% (with ethane conversion of 16.8%).

TABLE 21A Catalysts compositions (mole fractions) of NiTaCe and samplemass. “m” (mg) used in parallel fixed bed reactor screen. Row Col 1 2 34 5 6 1 Ni 0.9681 0.8950 0.8178 0.7362 0.6498 0.5580 Ta 0.0319 0.10500.1822 0.2638 0.3502 0.4420 Ce 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000m 40.8 46.6 52.6 55.3 45.2 50.8 2 Ni 0.9569 0.8844 0.8079 0.7270 0.64140.5507 Ta 0.0316 0.1038 0.1800 0.2605 0.3457 0.4361 Ce 0.0115 0.01180.0121 0.0125 0.0128 0.0132 m 46.7 47.1 50.6 52.7 51.6 56.3 3 Ni 0.94610.8741 0.7982 0.7181 0.6333 0.5435 Ta 0.0312 0.1026 0.1778 0.2573 0.34140.4304 Ce 0.0227 0.0233 0.0239 0.0246 0.0253 0.0261 m 51.6 45.5 47.243.1 52.7 58.8 4 Ni 0.9355 0.8641 0.7888 0.7094 0.6254 0.5365 Ta 0.03090.1014 0.1757 0.2542 0.3371 0.4249 Ce 0.0337 0.0346 0.0355 0.0365 0.03750.0386 m 44.1 52.2 46.3 53.3 47.6 56.9 5 Ni 0.9251 0.8542 0.7796 0.70080.6177 0.5297 Ta 0.0305 0.1002 0.1737 0.2511 0.3329 0.4195 Ce 0.04440.0456 0.0468 0.0481 0.0494 0.0508 m 49.2 55.7 44.1 43.0 54.1 55.6 6 Ni0.9149 0.8446 0.7706 0.6925 0.6101 0.5230 Ta 0.0302 0.0991 0.1716 0.24810.3289 0.4142 Ce 0.0549 0.0563 0.0578 0.0594 0.0610 0.0628 m 45.6 58.145.5 45 58.4 55.1

NiNbCe catalyst compositions were prepared by several different methods,including freeze drying, precipitation with tetraethylammoniumhydroxide, and precipitation with ammonium carbonate, and then screenedas discussed below. Briefly, in the freeze drying method, NiNbCecatalyst compositions were prepared by combining various amounts of theaqueous metal salt solutions to form a catalyst precursor solution, andthen freeze drying to remove water. The NiNbCe catalyst compositionsprepared by precipitation with tetraethylammonium hydroxide wereprepared substantially as described in Example 1, using cerium nitrate([Ce]=1.00 M), and using tetraethylammonium hydroxide as theprecipitating agent. In each of these two cases, the resulting solidmaterials were calcined by heating to 120° C. at 1° C./min and dwellingat 120° C. for 2 hours, subsequently, heating to 180° C. at 1° C./minand dwelling at 180° C. for 2 hours, subsequently heating to 400° C. at2° C./min and dwelling at 400° C. for 8 hours. The NiNbCe catalystcompositions prepared by precipitation with ammonium carbonate wereprepared substantially as described in Example 1, using cerium nitrate([Ce]=1.00 M), and using ammonium carbonate as the precipitating agent.In this cases, the resulting solid material was calcined by heating to300° C. at 2° C./min and dwelling at 300° C. for 8 hours in air. Thecompositions and amounts of the various NiNbCe catalyst compositions areshown in Table 21B (prepared by freeze drying), Table 21C (prepared byprecipitation with tetraethylammonium hydroxide) and Table 21D (preparedby precipitation with ammonium carbonate).

The NiNbCe catalysts of Table 21B—prepared by freeze drying—werescreened in the fixed bed parallel reactor for oxidative ethanedehydrogenation at 300° C. with flowrates of ethane:nitrogen:oxygen of0.42:0.54:0.088 sccm. Ethane conversion values for the NiNbCe oxidecompositions ranged from 6.6% (with ethylene selectivity of 61.8%) to11.7% (with ethylene selectivity of 71.6%), and ethylene selectivityvalues ranged from 61.3% (with ethane conversion of 8.5%) to 74.3% (withethane conversion of 10.5%).

The NiNbCe catalysts of Table 21C—prepared by precipitation withtetraethylammonium hydroxide—were likewise screened in the fixed bedparallel reactor for oxidative ethane dehydrogenation at 300° C. withflowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm. Ethaneconversion values for the NiNbCe oxide compositions ranged from 7.5%(with ethylene selectivity of 78.8%) to 18.8% (with ethylene selectivityof 85.7%), and ethylene selectivity values ranged from 58.9% (withethane conversion of 10.1%) to 85.7% (with ethane conversion of 18.8%).These catalysts were also screened in the parallel fixed bed reactor atdifferent flowrates (300° C.; ethane:nitrogen:oxygen flow of0.10:0.85:0.088 sccm) (data not shown).

The NiNbCe catalysts of Table 21D—prepared by precipitation withammonium carbonate—were likewise screened in the fixed bed parallelreactor for oxidative ethane dehydrogenation at 300° C. with flowratesof ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm. Ethane conversionvalues for the NiNbCe oxide compositions ranged from 16.7% (withethylene selectivity of 78.1%) to 19.1% (with ethylene selectivity of81.5%), and ethylene selectivity values ranged from 78.1% (with ethaneconversion of 16.7%) to 83.5% (with ethane conversion of 18.5%). Thesecatalysts were also screened in an ethylene co-feed (mixed feed)experiment (data not shown). These catalysts were also screened againafter being recalcined by heating to 400° C. at 2° C./min and dwellingat 400° C. for 8 hours in air. (data not shown).

Table 21B. Catalyst compositions (mole fractions) of NiNbCe oxidecatalysts prepared by freeze drying and sample mass (mg) used inparallel fixed bed reactor screen.

TABLE 21B Catalyst compositions (mole fractions) of NiNbCe oxidecatalysts prepared by freeze drying and sample mass (mg) used inparallel fixed bed reactor screen. Row Column 1 2 3 4 5 6 7 1 Ni 0.907Nb 0.068 Ce 0.024 Mass 41.5 (mg) 2 Ni 0.860 0.850 Nb 0.069 0.126 Ce0.070 0.025 Mass 44.9 39.7 (mg) 3 Ni 0.812 0.802 0.792 Nb 0.071 0.1280.183 Ce 0.118 0.071 0.025 Mass 43.1 40.4 37.4 (mg) 4 Ni 0.762 0.7520.743 0.734 Nb 0.072 0.130 0.186 0.242 Ce 0.166 0.118 0.071 0.025 Mass44.2 39.7 38.7 38.0 (mg) 5 Ni 0.710 0.701 0.692 0.684 0.675 Nb 0.0730.132 0.189 0.246 0.300 Ce 0.217 0.167 0.118 0.071 0.025 Mass 39.3 43.137.8 43.6 39.7 (mg) 6 Ni 0.657 0.648 0.640 0.632 0.624 0.616 Nb 0.0740.134 0.193 0.250 0.305 0.359 Ce 0.269 0.218 0.168 0.119 0.071 0.025Mass 40.8 52.7 36.6 37.9 39.1 38.7 (mg) 7 Ni 0.601 0.593 0.586 0.5780.571 0.563 0.556 Nb 0.075 0.137 0.196 0.254 0.310 0.365 0.419 Ce 0.3230.270 0.219 0.168 0.119 0.072 0.025 Mass 42.3 38.7 44.9 35.1 35.8 37.436.1 (mg)

TABLE 21C Catalyst compositions (mole fractions) of NiNbCe oxidecatalysts prepared by precipitation with tetraethylammonium hydroxideand sample mass (mg) used in parallel fixed bed reactor screen. RowColumn 1 2 3 4 5 6 1 Ni 0.942 Nb 0.058 Ce 0.000 Mass 52.7 (mg) 2 Ni0.921 0.870 Nb 0.060 0.131 Ce 0.019 0.000 Mass 43.6 42.7 (mg) 3 Ni 0.8980.847 0.801 Nb 0.062 0.134 0.199 Ce 0.040 0.019 0.000 Mass 46.4 53.151.3 (mg) 4 Ni 0.875 0.823 0.778 0.737 Nb 0.064 0.138 0.204 0.263 Ce0.062 0.039 0.018 0.000 Mass 54.0 50.7 49.8 51.2 (mg) 5 Ni 0.849 0.7980.752 0.712 0.675 Nb 0.066 0.142 0.210 0.270 0.325 Ce 0.085 0.060 0.0380.018 0.000 Mass 48.0 52.9 52.1 49.2 52.9 (mg) 6 Ni 0.822 0.771 0.7260.686 0.650 0.617 Nb 0.068 0.147 0.216 0.278 0.333 0.383 Ce 0.110 0.0820.058 0.037 0.017 0.000 Mass 51.0 45.2 49.9 45.3 48.7 50.2 (mg)

TABLE 21D Catalyst compositions (mole fractions) of NiNbCe oxidecatalysts prepared by precipitation with ammonium-carbonate and samplemass (mg) used in parallel fixed bed reactor screen. Row Column 1 2 3 45 6 1 Ni 0.890 Nb 0.110 Ce 0.000 mass 48.5 (mg) 2 Ni 0.879 0.810 Nb0.115 0.190 Ce 0.007 0.000 mass 48.1 49.0 (mg) 3 Ni 0.867 0.796 0.736 Nb0.119 0.198 0.264 Ce 0.014 0.006 0.000 mass 55.2 46.2 51.6 (mg) 4 Ni0.854 0.782 0.721 0.668 Nb 0.125 0.205 0.273 0.332 Ce 0.022 0.013 0.0060.000 mass 51.0 51.5 54.7 47.9 (mg) 5 Ni 0.840 0.766 0.704 0.651 0.606Nb 0.130 0.214 0.284 0.343 0.394 Ce 0.030 0.021 0.013 0.006 0.000 mass51.9 54.4 51.4 54.4 53.4 (mg) 6 Ni 0.824 0.749 0.686 0.632 0.587 0.547Nb 0.136 0.223 0.295 0.356 0.408 0.453 Ce 0.039 0.029 0.020 0.012 0.0060.000 mass 45.4 52.7 49.1 49.0 47.8 52.8 (mg)

NiNbTaCe catalyst compositions were prepared in bulk by precipitationsubstantially as described in connection with Example 1, using ceriumnitrate ([Ce]=1.00 M) aqueous stock solution, and calcining by heatingto 350° C. at 2° C./min and maintaining at 350° C. for 8 hours in air.The compositions and amounts of the various NiTaCe catalyst compositionsare shown in Table 21E.

The NiNbTaCe oxide catalysts were initially screened in the fixed bedparallel reactor for oxidative ethane dehydrogenation at 300° C. withflowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm. Ethaneconversion values for the NiNbTaCe oxide compositions ranged from 16.8%(with ethylene selectivity of 83.4%) to 20.8% (with ethylene selectivityof 84.0%), and ethylene selectivity values ranged from 81.6% (withethane conversion of 17.9%) to 84.0% (with ethane conversion of 20.8%).

The NiNbTaCe oxide catalysts were screened again in the fixed bedparallel reactor for oxidative ethane dehydrogenation at twice theflowrates as compared to the initial screen (300° C.;ethane:nitrogen:oxygen flow of 0.84:1.08:0.176 sccm). Ethane conversionvalues for the NiNbTaCe oxide compositions ranged from 11.6% (withethylene selectivity of 83.2%) to 16.6% (with ethylene selectivity of84.2%), and ethylene selectivity values ranged from 80.0% (with ethaneconversion of 12.7%) to 84.3% (with ethane conversion of 15.5%).

Table 21E. Catalyst compositions (mole fractions) of NiNbTaCe oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen.

TABLE 21E Row Column 1 2 3 4 5 6 7 8 1 Ni 0.988 Nb 0.000 Ta 0.000 Ce0.012 mass 49.2 (mg) 2 Ni 0.899 0.904 Nb 0.000 0.085 Ta 0.090 0.000 Ce0.011 0.012 mass 45.3 47.5 (mg) 3 Ni 0.815 0.820 0.824 Nb 0.000 0.0820.165 Ta 0.174 0.087 0.000 Ce 0.011 0.011 0.011 mass 52.8 53.5 47.4 (mg)4 Ni 0.738 0.741 0.745 0.749 Nb 0.000 0.079 0.159 0.240 Ta 0.252 0.1690.085 0.000 Ce 0.011 0.011 0.011 0.011 mass 52.3 51.7 51.4 51.4 (mg) 5Ni 0.665 0.668 0.671 0.675 0.678 Nb 0.000 0.077 0.154 0.232 0.311 Ta0.325 0.245 0.164 0.083 0.000 Ce 0.010 0.010 0.010 0.011 0.011 mass 53.153.0 53.8 50.2 45.1 (mg) 6 Ni 0.596 0.599 0.602 0.605 0.608 0.611 Nb0.000 0.074 0.149 0.225 0.302 0.379 Ta 0.394 0.316 0.238 0.160 0.0800.000 Ce 0.010 0.010 0.010 0.010 0.010 0.010 mass 55.2 47.8 51.3 48.947.1 49.7 (mg) 7 Ni 0.532 0.535 0.537 0.540 0.542 0.545 0.547 Nb 0.0000.072 0.145 0.218 0.292 0.367 0.443 Ta 0.458 0.384 0.308 0.232 0.1560.078 0.000 Ce 0.010 0.010 0.010 0.010 0.010 0.010 0.010 mass 52.5 50.148.8 45.8 55.1 53.0 47.5 (mg) 8 Ni 0.472 0.474 0.476 0.478 0.480 0.4830.485 0.487 Nb 0.000 0.070 0.141 0.212 0.284 0.356 0.429 0.503 Ta 0.5190.447 0.374 0.301 0.226 0.152 0.076 0.000 Ce 0.009 0.010 0.010 0.0100.010 0.010 0.010 0.010 mass 53.8 53.0 45.7 45.0 49.5 48.9 52.0 46.5(mg)

Example 22 ODHE Over NiTaYb/NiNbYb Oxide Catalysts (#13947/#13946)

Catalyst compositions comprising various NiTaY and NiNbYb oxides wereprepared in small (˜100 mg) quantities by precipitation substantially asdescribed in connection with Example 1, using ytterbium nitratepentahydrate ([Yb]=0.456M) aqueous stock solution and calcining at 300°C., as described. The compositions and amounts of the various catalystcompositions are shown in Table 22A (NiTaYb) and Table 22B (NiNbYb).

The NiTaYb oxide catalysts were screened in the fixed bed parallelreactor for oxidative ethane dehydrogenation at 300° C. with flowratesof ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm. Ethane conversionvalues for the NiTaYb oxide compositions ranged from 13.5% (withethylene selectivity of 75.1%) to 20.0% (with ethylene selectivity of83.9%), and ethylene selectivity values ranged from 75.1% (with ethaneconversion of 13.5%) to 84.7% (with ethane conversion of 19.1%).

The NiNbYb oxide catalysts were likewise screened in the fixed bedparallel reactor for oxidative ethane dehydrogenation at 300° C. withflowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm. Ethaneconversion values for the NiNbYb oxide compositions ranged from 10.5%(with ethylene selectivity of 68.8%) to 19.4% (with ethylene selectivityof 83.0%), and ethylene selectivity values ranged from 68.8% (withethane conversion of 10.5%) to 84.0% (with ethane conversion of 18.3%).

TABLE 22A Catalyst compositions (mole fractions) of NiTaYb oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen. Row Column 1 2 3 4 5 6 1 Ni 0.879 Ta 0.121 Yb 0.000 mass 51.2(mg) 2 Ni 0.855 0.793 Ta 0.124 0.207 Yb 0.021 0.000 mass 53.9 51.0 (mg)3 Ni 0.831 0.768 0.715 Ta 0.127 0.212 0.285 Yb 0.042 0.019 0.000 mass51.0 54.0 54.6 (mg) 4 Ni 0.805 0.743 0.690 0.644 Ta 0.131 0.217 0.2910.356 Yb 0.065 0.040 0.019 0.000 mass 49.5 52.6 53.2 50.5 (mg) 5 Ni0.777 0.716 0.664 0.619 0.580 Ta 0.134 0.222 0.298 0.363 0.420 Yb 0.0890.061 0.038 0.018 0.000 mass 49.4 47.9 50.8 52.7 47.8 (mg) 6 Ni 0.7490.688 0.637 0.593 0.555 0.521 Ta 0.138 0.228 0.305 0.371 0.429 0.479 Yb0.114 0.084 0.058 0.036 0.017 0.000 mass 51.6 54.0 53.4 53.3 52.5 53.1(mg)

TABLE 22B Catalyst compositions (mole fractions) of NiNbYb oxidecatalysts and sample mass (mg) used in parallel fixed bed reactorscreen. Row Column 1 2 3 4 5 6 1 Ni 0.896 Nb 0.104 Yb 0.000 mass 51.8(mg) 2 Ni 0.873 0.820 Nb 0.107 0.180 Yb 0.021 0.000 mass 49.0 54.5 (mg)3 Ni 0.848 0.795 0.749 Nb 0.109 0.185 0.251 Yb 0.043 0.020 0.000 mass53.7 48.8 45.9 (mg) 4 Ni 0.822 0.770 0.724 0.683 Nb 0.112 0.189 0.2570.317 Yb 0.066 0.041 0.019 0.000 mass 52.5 52.2 46.2 52.4 (mg) 5 Ni0.794 0.743 0.697 0.657 0.622 Nb 0.115 0.194 0.263 0.324 0.378 Yb 0.0910.063 0.040 0.019 0.000 mass 52.0 49.1 48.3 52.2 53.4 (mg) 6 Ni 0.7650.714 0.670 0.630 0.595 0.564 Nb 0.118 0.199 0.269 0.331 0.387 0.436 Yb0.116 0.087 0.061 0.038 0.018 0.000 mass 49.9 51.8 48.9 46.8 54.8 47.6(mg)

Example 23 ODHE Over NiTaEr/NiNbEr Oxide Catalysts (#13950)

Catalyst compositions comprising various NiTaEr and NiNbEr oxides wereprepared in small (˜100 mg) quantities by precipitation substantially asdescribed in connection with Example 1, using erbium acetate hydrate([Er]=0.268 M) aqueous stock solution and calcining at 300° C., asdescribed. The compositions and amounts of the various NiTaEr and NiNbEroxide catalyst compositions are shown in Table 23A.

The NiTaEr and NiNbEr oxide catalysts (˜50 mg) were screened in thefixed bed parallel reactor for oxidative ethane dehydrogenation at 300°C. with flowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm.Ethane conversion values for the NiTaEr oxide compositions ranged from12.9% (with ethylene selectivity of 69.7%) to 19.4% (with ethyleneselectivity of 83.5%), and ethylene selectivity values ranged from 69.7%(with ethane conversion of 12.9%) to 84.1% (with ethane conversion of17.9%). Ethane conversion values for the NiNbEr oxide compositionsranged from 12.5% (with ethylene selectivity of 65.0%) to 20.9% (withethylene selectivity of 83.9%), and ethylene selectivity values rangedfrom 65.0% (with ethane conversion of 12.5%) to 85.0% (with ethaneconversion of 18.2%).

The NiTaEr and NiNbEr oxide catalysts (˜50 mg) were screened again inthe fixed bed parallel reactor for oxidative ethane dehydrogenation at adifferent temperature (250° C.; ethane:nitrogen:oxygen flow of0.42:0.54:0.088 sccm). Ethane conversion values for the NiTaEr oxidecompositions ranged from 3.6% (with ethylene selectivity of 55.1%) to7.8% (with ethylene selectivity of 65.0%), and ethylene selectivityvalues ranged from 55.1% (with ethane conversion of 3.6%) to 76.6% (withethane conversion of 7.1%). Ethane conversion values for the NiNbEroxide compositions ranged from 3.5% (with ethylene selectivity of 44.3%)to 7.4% (with ethylene selectivity of 74.4%), and ethylene selectivityvalues ranged from 44.3% (with ethane conversion of 3.5%) to 83.6% (withethane conversion of 6.6%).

TABLE 23A Catalyst compositions (mole fractions) of NiTaEr/NiNbEr oxidecatalysts used in parallel fixed bed reactor screen. Row Col 1 2 3 4 5 61 Ni 1.000 0.919 0.842 0.768 0.696 0.628 Nb 0.000 0.000 0.000 0.0000.000 0.000 Ta 0.000 0.081 0.158 0.232 0.304 0.372 Er 0.000 0.000 0.0000.000 0.000 0.000 2 Ni 0.915 0.967 0.884 0.806 0.730 0.658 Nb 0.0850.000 0.000 0.000 0.000 0.000 Ta 0.000 0.000 0.083 0.163 0.239 0.311 Er0.000 0.033 0.032 0.032 0.031 0.030 3 Ni 0.835 0.881 0.932 0.848 0.7680.691 Nb 0.165 0.087 0.000 0.000 0.000 0.000 Ta 0.000 0.000 0.000 0.0860.167 0.245 Er 0.000 0.032 0.068 0.067 0.065 0.064 4 Ni 0.759 0.7990.844 0.895 0.809 0.728 Nb 0.241 0.170 0.090 0.000 0.000 0.000 Ta 0.0000.000 0.000 0.000 0.088 0.172 Er 0.000 0.031 0.066 0.105 0.103 0.100 5Ni 0.686 0.722 0.761 0.806 0.855 0.768 Nb 0.314 0.248 0.174 0.092 0.0000.000 Ta 0.000 0.000 0.000 0.000 0.000 0.091 Er 0.000 0.031 0.064 0.1020.145 0.141 6 Ni 0.617 0.648 0.683 0.721 0.764 0.813 Nb 0.383 0.3220.255 0.179 0.095 0.000 Ta 0.000 0.000 0.000 0.000 0.000 0.000 Er 0.0000.030 0.063 0.099 0.140 0.187

Example 24 ODHE over NiTaDy/NiNbDy Oxide Catalysts (#13949)

Catalyst compositions comprising various NiTaDy and NiNbDy oxides wereprepared in small (˜100 mg) quantities by precipitation substantially asdescribed in connection with Example 1, using dysprosium acetate hydrate([Dy]=0.294 M) aqueous stock solution and calcining at 300° C., asdescribed. The compositions and amounts of the various NiTaDy and NiNbDyoxide catalyst compositions are shown in Table 24A.

The NiTaDy and NiNbDy oxide catalysts (˜50 mg) were screened in thefixed bed parllel reactor for oxidative ethane dehydrogenation at 300°C. with flowrates of ethane:nitrogen:oxygen of 0.42:0.54:0.088 sccm.Ethane conversion values for the NiTaDy oxide compositions ranged from14.1% (with ethylene selectivity of 71.2%) to 19.9% (with ethyleneselectivity of 84.4%), and ethylene selectivity values ranged from 71.2%(with ethane conversion of 14.1%) to 84.7% (with ethane conversion of17.3%). Ethane conversion values for the NiNbDy oxide compositionsranged from 10.9% (with ethylene selectivity of 63.1%) to 18.9% (withethylene selectivity of 82.7%), and ethylene selectivity values rangedfrom 63.1% (with ethane conversion of 10.9%) to 84.7% (with ethaneconversion of 18.4%).

The NiTaDy and NiNbDy oxide catalysts ( 50 mg) were screened again inthe fixed bed parallel reactor for oxidative ethane dehydrogenation at adifferent temperature (250° C.; ethane:nitrogen:oxygen flow of0.42:0.54:0.088 sccm). (data not shown). These catalysts were alsofurther calcined at 400°, and then screened again, in separateexperiments, at 250° C. and at 300° C., in each case withethane:nitrogen:oxygen flow of 0.42:0.54:0.088 sccm. (data not shown).

TABLE 24A Catalyst compositions (mole fractions) of NiTaDy/NiNbDy oxidecatalysts used in parallel fixed bed reactor screen. Row Col 1 2 3 4 5 61 Ni 1.000 0.919 0.842 0.768 0.696 0.628 Nb 0.000 0.000 0.000 0.0000.000 0.000 Ta 0.000 0.081 0.158 0.232 0.304 0.372 Dy 0.000 0.000 0.0000.000 0.000 0.000 2 Ni 0.915 0.964 0.882 0.803 0.728 0.656 Nb 0.0850.000 0.000 0.000 0.000 0.000 Ta 0.000 0.000 0.083 0.162 0.238 0.311 Dy0.000 0.036 0.035 0.035 0.034 0.033 3 Ni 0.835 0.878 0.926 0.842 0.7630.687 Nb 0.165 0.087 0.000 0.000 0.000 0.000 Ta 0.000 0.000 0.000 0.0850.166 0.244 Dy 0.000 0.035 0.074 0.072 0.071 0.069 4 Ni 0.759 0.7970.839 0.886 0.801 0.721 Nb 0.241 0.169 0.089 0.000 0.000 0.000 Ta 0.0000.000 0.000 0.000 0.087 0.170 Dy 0.000 0.034 0.072 0.114 0.112 0.109 5Ni 0.686 0.720 0.757 0.798 0.843 0.758 Nb 0.314 0.247 0.173 0.091 0.0000.000 Ta 0.000 0.000 0.000 0.000 0.000 0.090 Dy 0.000 0.033 0.070 0.1110.157 0.153 6 Ni 0.617 0.646 0.679 0.714 0.754 0.799 Nb 0.383 0.3210.253 0.178 0.094 0.000 Ta 0.000 0.000 0.000 0.000 0.000 0.000 Dy 0.0000.033 0.068 0.108 0.152 0.201

Example 25 ODHE Over NiNbSr/NitNbCs Oxide Catalysts (#16892)

Catalyst compositions comprising various NiNbSr and NiNbCs oxides wereprepared in small (˜100 mg) quantities dispensing various amounts ofaqueous metal solutions (nickel nitrate ([Ni]=1.0M), niobium oxalate([Nb]=0.569M, excess oxalic acid [H⁺]=0.346M), strontium nitrate([Sr]=1.0M), and cesium nitrate ([Cs]=1.00M) with an automated liquidhandling robot into an array of glass vials in an aluminum substrate.Magnetic stirbars were added to each of the glass vials, and theprecursor solutions were heated at 120° C. on a hot place with vigorousmagnetic stirring, such that the water in the solutions boiled off afterabout 2 hours. The dried materials were then calcined by heating to 320°C. at 5° C./min and are dwelling at 320° C. for 8 hours in air, andsubsequently cooled to 25° C. The compositions and amounts of thevarious NiNbSr and NiNbCs oxide catalyst compositions are shown in Table25A.

The NiNbSr and NiNbCs oxide catalysts (˜50 mg) were screened in thefixed bed parallel reactor for oxidative ethane dehydrogenation at 300°C. with flowrates of ethane:oxygen of 0.42:0.058 sccm. Ethane conversionvalues for the NiNbSr oxide compositions ranged from 17.4% (withethylene selectivity of 84.4%) to 22.0% (with ethylene selectivity of87.5%), and ethylene selectivity values ranged from 82.3% (with ethaneconversion of 18.1%) to 89.6% (with ethane conversion of 21.2%). Ethaneconversion (C) and ethylene selectivity (S) values for the NiNbCs oxidecompositions ranged from 5.2% C, 15.2% S to 21.7% C, 87.5% S.

The NiNbSr and NiNbCs oxide catalysts (˜50 mg) were screened again inthe fixed bed parallel reactor for oxidative ethane dehydrogenation at adifferent temperature and different flowrates (275° C.; ethane:oxygenflow of 0.42:0.033 sccm). Ethane conversion values for the NiNTbSr oxidecompositions ranged from 10.6% (with ethylene selectivity of 84.5%) to15.5% (with ethylene selectivity of 91.4%), and ethylene selectivityvalues ranged from 83.7% (with ethane conversion of 11.2%) to 91.4%(with ethane conversion of 15.5%). Ethane conversion (C) and ethyleneselectivity (S) values for the NiNbCs oxide compositions ranged from3.3% C, 14.4% S to 14.4% C, 90.1% S.

TABLE 25A Catalyst compositions (mole fractions) of NiNbSr/NiNbCs oxidecatalysts used in parallel fixed bed reactor screen. Row Column 1 2 3 45 6 1 Ni 0.898 0.883 0.867 0.850 0.832 0.812 Nb 0.102 0.106 0.110 0.1140.118 0.123 Sr 0.000 0.000 0.000 0.000 0.000 0.000 Cs 0.000 0.011 0.0230.036 0.050 0.065 mass 51.2 51.5 51.4 50.0 48.3 54.2 (mg) 2 Ni 0.8830.823 0.806 0.788 0.769 0.748 Nb 0.106 0.177 0.183 0.190 0.197 0.204 Sr0.011 0.000 0.000 0.000 0.000 0.000 Cs 0.000 0.000 0.011 0.022 0.0350.048 mass 53.2 50.1 50.9 51.8 51.3 47.5 (mg) 3 Ni 0.867 0.806 0.7530.734 0.714 0.693 Nb 0.110 0.183 0.247 0.256 0.264 0.273 Sr 0.023 0.0110.000 0.000 0.000 0.000 Cs 0.000 0.000 0.000 0.010 0.021 0.033 mass 52.452.1 51.6 49.500 48.300 51.100 (mg) 4 Ni 0.850 0.788 0.734 0.687 0.6670.646 Nb 0.114 0.190 0.256 0.313 0.323 0.333 Sr 0.036 0.022 0.010 0.0000.000 0.000 Cs 0.000 0.000 0.000 0.000 0.010 0.021 mass 52.2 50.6 53.851.5 52.300 54.400 (mg) 5 Ni 0.832 0.769 0.714 0.667 0.626 0.605 Nb0.118 0.197 0.264 0.323 0.374 0.385 Sr 0.050 0.035 0.021 0.010 0.0000.000 Cs 0.000 0.000 0.000 0.000 0.000 0.010 mass 46.4 51.1 49.2 51.549.9 54.200 (mg) 6 Ni 0.812 0.748 0.693 0.646 0.605 0.569 Nb 0.123 0.2040.273 0.333 0.385 0.431 Sr 0.065 0.048 0.033 0.021 0.010 0.000 Cs 0.0000.000 0.000 0.000 0.000 0.000 mass 52.3 53.6 50.0 48.8 50.5 54.4 (mg)

Example 26 Lifetime Tests for ODHE Over Ni(Nb, Ta, Ti, Zr)-based OxideCatalysts

In a first set of experiments, long-term stability and performancecharacteristics of various Ni(Nb, Ta, Ti, Zr)(Ce, Dy, Er, Nd, Sm, Yb,Pr, Gd, Sb, Bi) oxide catalysts were evaluated in a 200 hour lifetimetest. In a second set of experiments, long-term stability andperformance characteristics of various Ni(Nb, Ta, Ti)(Sm, Sn, Co, Cs,Sb, Ag)(Mg, Ca, Li) oxide catalysts were evaluated in a 400 hourlifetime test. As described below, compositions and preparation methodswere varied in the lifetime tests. Test conditions were, in the 200 hourtest, also varied (data not shown).

200 Hour Lifetime Test

In the 200 hour lifetime test, forty-two different Ni(Nb, Ta, Ti,Zr)(Ce, Dy, Er, Nd, Sm, Yb, Pr, Gd, Sb, Bi) oxide catalysts wereprepared according to one of the following methods, designated as MethodA through Method F. The various catalyst compositions and their methodof preparation are shown in Table 26A.

Method A: Catalysts were prepared by precipitation withtetramethylammonium hydroxide to the mixed metal nitrate or oxalatesolution. After centrifugation, the solid materials obtained were driedat 60° C. under vacuum, and then calcined to 300° C. at 2° C./min anddwelled at 300° C. for 8 hrs.

Method B: Catalysts were prepared by precipitation withtetramethylammonium hydroxide to the mixed metal nitrate or oxalatesolution. After centrifugation, the solid materials obtained were driedat 60° C. under vacuum, and then calcined to 300° C. at 2° C./min anddwelled at 300° C. for 8 hrs. After cooling down to 25° C., thosecatalysts were calcined again to 400° C. at 2° C./min and dwell at 400°C. for 8 hrs.

Method C: Catalysts were prepared by precipitation with ammoniumcarbonate to the mixed metal nitrate or oxalate solution. Aftercentrifugation, the solid materials obtained were dried at 60° C. undervacuum, and then calcined to 300° C. at 2° C./min and dwelled at 300° C.for 8 hrs.

Method D: Catalysts were prepared by precipitation with ammoniumcarbonate to the mixed metal nitrate or oxalate solution. Aftercentrifugation, the solid-materials obtained were dried at 60° C. undervacuum, and then calcined to 300° C. at 2° C./min and dwelled at 300° C.for 8 hrs. After cooling down to 25° C., those catalysts were calcinedagain to 400° C. at 2° C./min and dwell at 400° C. for 8 hrs.

Method E: TiO₂ support in pellet form was dried at 100° C. for over 8hrs. After cooling to 25° C., TiO₂ support was impregnated with themixed metal nitrate or oxalate solution. After centrifugation, the solidmaterials obtained were dried at 60° C. under vacuum, and then calcinedto 300° C. at 2° C./min and dwelled at 300° C. for 8 hrs.

Method F: Catalysts were prepared by precipitation withtetramethylammonium hydroxide to the mixed metal nitrate or oxalatesolution. After centrifugation, the solid materials obtained are driedat 60° C. under vacuum, and then calcined to 400° C. at 2° C./min anddwelled at 400° C. for 8 hrs.

The forty-two catalysts of Table 26A (˜50 mg), together with six blanks,were screened simultaneously in the 48-channel parallel fixed bedreactor for oxidative ethane dehydrogenation at 300° C. withethane:nitrogen:oxygen flow of 0.42:0.54:0.088 sccm. Table 26Bsummarizes the amount of catalyst screened, as well as the ethaneconversion (C) and ethylene selectivity (S) for each of the catalysts,measured after various times during the test.

TABLE 26A Catalyst composition and preparation methods for catalystsscreened in 200 hour lifetime test. Catalyst Preparation CompositionMethod Part A Ni_(0.86)Ta_(0.14)O_(x) A Ni_(0.65)Ta_(0.31)Ce_(0.04)O_(x)A Ni_(0.62)Nb_(0.19)Ta_(0.19)Ce_(0.01)O_(x) ANi_(0.73)Ta_(0.24)Dy_(0.03)O_(x) A Ni_(0.68)Nb_(0.25)Dy_(0.07)O_(x) ANi_(0.68)Nb_(0.26)Er_(0.06)O_(x) A Blank n/a Ni_(0.62)Nb_(0.38)O_(x) ANi_(0.71)Ta_(0.23)Nd_(0.06)O_(x) A Ni_(0.63)Nb_(0.34)Sm_(0.03)O_(x) ANi_(0.54)Ta_(0.45)Sm_(0.01)O_(x) A Ni_(0.72)Ti_(0.28)O_(x) ANi_(0.66)Ti_(0.29)Yb_(0.05)O_(x) A blank n/a Part BNi_(0.62)Nb_(0.34)Ce_(0.04)O_(x) B Ni_(0.62)Ta_(0.34)Ce_(0.04)O_(x) BNi_(0.76)Nb_(0.17)Er_(0.06)O_(x) B Ni_(0.68)Ta_(0.25)Dy_(0.07)O_(x) BNi_(0.60)Nb_(0.19)Ta_(0.18)Sm_(0.03)O_(x) BNi_(0.64)Nb_(0.34)Pr_(0.02)O_(x) B blank n/a Ni_(0.63)Nb_(0.37)O_(x) BNi_(0.51)Ta_(0.42)Zr_(0.07)O_(x) B Ni_(0.73)Ti_(0.27)O_(x) BNi_(0.58)Ta_(0.34)Gd_(0.07)O_(x) B Ni_(0.68)Nb_(0.24)Gd_(0.08)O_(x) BNi_(0.80)Nb_(0.19)Sb_(0.01)O_(x) B blank n/aNi_(0.82)Nb_(0.14)Sb_(0.04)O_(x) B Ni_(0.60)Nb_(0.39)Sb_(0.01)O_(x) ANi_(0.72)Nb_(0.27)Bi_(0.01)O_(x) B Ni_(0.73)Ta_(0.25)Bi_(0.02)O_(x) BNi_(0.63)Nb_(0.33)Yb_(0.04)O_(x) B Ni_(0.59)Ta_(0.37)Yb_(0.04)O_(x) Bblank n/a Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) CNi_(0.71)Nb_(0.27)Sb_(0.02)O_(x) C Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) DNi_(0.63)Nb_(0.19)Ta_(0.18)O_(x)/TiO₂ E Ni_(0.71)Nb_(0.27)Sb_(0.02)O_(x)D Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) F blank n/aNi_(0.74)Nb_(0.08)Ta_(0.17)Ce_(0.01)O_(x) FNi_(0.75)Nb_(0.24)Ce_(0.01)O_(x) F Ni_(0.53)Ta_(0.40)Gd_(0.07)O_(x) ANi_(0.74)Nb_(0.08)Ta_(0.17)Ce_(0.01)O_(x) ANi_(0.74)Ta_(0.22)Yb_(0.04)O_(x) A Ni_(0.65)Ta_(0.36)Bi_(0.01)O_(x) A

TABLE 26B Catalyst composition, sample mass (mg) and ethane conversion(C) and ethylene selectivity (S) measured at various times on streamduring screening in 200 hour lifetime test. Time on stream (hour) 5.3462.37 Mass C S C S Library # (mg) (%) (%) (%) (%) Part A1Ni_(0.86)Ta_(0.14)O_(x) 49.4 18.1 83.5 18.2 83.3Ni_(0.65)Ta_(0.31)Ce_(0.04)O_(x) 50 17.8 82.4 18.5 82.8Ni_(0.62)Nb_(0.19)Ta_(0.19)Ce_(0.01)O_(x) 50.4 16.4 84.3 14.3 84.6Ni_(0.73)Ta_(0.24)Dy_(0.03)O_(x) 50.5 19.1 83.8 18.9 84.2Ni_(0.68)Nb_(0.25)Dy_(0.07)O_(x) 49.8 18.6 83.6 18.9 83.6Ni_(0.68)Nb_(0.26)Er_(0.06)O_(x) 49.8 19.0 83.0 18.1 83.1 Blank n/a 0.146.0 0.1 46.7 Ni_(0.62)Nb_(0.38)O_(x) 49.2 19.6 85.2 18.2 85.5Ni_(0.71)Ta_(0.23)Nd_(0.06)O_(x) 49.6 17.3 81.5 17.0 81.8Ni_(0.63)Nb_(0.34)Sm_(0.03)O_(x) 50.4 21.1 85.0 20.3 85.2Ni_(0.54)Ta_(0.45)Sm_(0.01)O_(x) 49.5 17.4 84.5 16.2 84.2Ni_(0.72)Ti_(0.28)O_(x) 50 18.7 85.0 18.3 85.5Ni_(0.66)Ti_(0.29)Yb_(0.05)O_(x) 49.5 17.5 82.6 17.5 81.4 blank n/a 0.145.6 0.1 45.2 Ni_(0.62)Nb_(0.34)Ce_(0.04)O_(x) 42.6 15.7 81.0 14.9 81.8Ni_(0.62)Ta_(0.34)Ce_(0.04)O_(x) 47.6 14.7 81.7 14.9 82.3Ni_(0.76)Nb_(0.17)Er_(0.06)O_(x) 45 13.4 84.8 12.6 84.7Ni_(0.68)Ta_(0.25)Dy_(0.07)O_(x) 44.2 13.2 83.3 11.9 83.2Ni_(0.60)Nb_(0.19)Ta_(0.18)Sm_(0.03)O_(x) 45.6 15.3 84.2 14.8 83.4Ni_(0.64)Nb_(0.34)Pr_(0.02)O_(x) 48.1 15.5 84.6 14.6 83.9 blank n/a 0.144.3 0.1 42.6 Ni_(0.63)Nb_(0.37)O_(x) 45.9 12.8 86.4 11.5 86.3Ni_(0.51)Ta_(0.42)Zr_(0.07)O_(x) 44.5 15.0 83.3 13.9 82.6Ni_(0.73)Ti_(0.27)O_(x) 45.8 12.6 83.7 11.2 83.5Ni_(0.58)Ta_(0.34)Gd_(0.07)O_(x) 45.6 10.4 83.5 9.4 83.2Ni_(0.68)Nb_(0.24)Gd_(0.08)O_(x) 55.2 14.0 79.5 13.2 78.0Ni_(0.80)Nb_(0.19)Sb_(0.01)O_(x) 48.6 14.0 85.6 12.4 85.5 blank n/a 0.138.5 0.1 37.9 Ni_(0.82)Nb_(0.14)Sb_(0.04)O_(x) 49.6 12.0 83.7 10.2 82.7Ni_(0.60)Nb_(0.39)Sb_(0.01)O_(x) 51.8 17.9 83.9 16.5 83.7Ni_(0.72)Nb_(0.27)Bi_(0.01)O_(x) 54.7 15.4 85.9 15.1 85.8Ni_(0.73)Ta_(0.25)Bi_(0.02)O_(x) 50 10.9 86.0 10.2 85.9Ni_(0.63)Nb_(0.33)Yb_(0.04)O_(x) 41.1 13.9 83.3 12.7 82.7Ni_(0.59)Ta_(0.37)Yb_(0.04)O_(x) 47.1 10.8 84.9 7.2 85.1 blank n/a 0.140.0 0.1 48.2 Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) 48.3 16.5 82.6 15.4 79.8Ni_(0.71)Nb_(0.27)Sb_(0.02)O_(x) 49.1 16.5 82.6 14.9 77.8 Part A2Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) 49.3 13.0 82.5 12.5 80.4Ni_(0.63)Nb_(0.19)Ta_(0.18)O_(x)/TiO₂ 145.9 7.9 89.1 5.9 89.8Ni_(0.71)Nb_(0.27)Sb_(0.02)O_(x) 51.5 11.2 81.5 8.8 77.6Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) 49.7 16.7 85.2 16.2 85.1 blank n/a 0.137.4 0.1 43.1 Ni_(0.74)Nb_(0.08)Ta_(0.17)Ce_(0.01)O_(x) 50 16.1 84.316.8 84.9 Ni_(0.75)Nb_(0.24)Ce_(0.01)O_(x) 50.2 19.4 85.8 19.1 86.4Ni_(0.53)Ta_(0.40)Gd_(0.07)O_(x) 48.9 16.8 78.8 16.2 77.4Ni_(0.74)Nb_(0.08)Ta_(0.17)Ce_(0.01)O_(x) 50.9 17.3 84.3 15.6 85.0Ni_(0.74)Ta_(0.22)Yb_(0.04)O_(x) 50.7 17.8 84.2 17.5 84.6Ni_(0.65)Ta_(0.36)Bi_(0.01)O_(x) 50.4 16.3 82.6 15.3 82.1

TABLE 263 108.24 189.3 207.98 Library # C(%) S(%) C(%) S(%) C(%) S(%)Part B1 Ni_(0.86)Ta_(0.14)O_(x) 17.0 83.2 17.4 83.1 18.0 83.1Ni_(0.65)Ta_(0.31)Ce_(0.04)O_(x) 17.8 82.5 16.6 82.0 17.8 82.1Ni_(0.62)Nb_(0.19)Ta_(0.19)Ce_(0.01)O_(x) 13.3 84.6 11.8 84.2 12.8 84.6Ni_(0.73)Ta_(0.24)Dy_(0.03)O_(x) 18.4 84.2 18.0 84.0 18.7 84.2Ni_(0.68)Nb_(0.25)Dy_(0.07)O_(x) 18.1 83.5 17.6 82.9 18.1 82.9Ni_(0.68)Nb_(0.26)Er_(0.06)O_(x) 17.9 83.0 17.2 82.4 18.2 82.3 Blank 0.148.3 0.1 44.1 0.1 45.3 Ni_(0.62)Nb_(0.38)O_(x) 17.5 85.1 16.3 84.7 16.984.9 Ni_(0.71)Ta_(0.23)Nd_(0.06)O_(x) 16.4 81.4 16.3 81.4 16.7 81.3Ni_(0.63)Nb_(0.34)Sm_(0.03)O_(x) 19.4 85.0 18.8 84.5 17.3 84.5Ni_(0.54)Ta_(0.45)Sm_(0.01)O_(x) 15.3 83.9 14.5 83.5 14.8 83.6Ni_(0.72)Ti_(0.28)O_(x) 17.7 85.2 17.4 85.1 17.4 85.0Ni_(0.66)Ti_(0.29)Yb_(0.05)O_(x) 17.0 80.5 16.5 79.1 15.6 79.0 blank 0.143.8 0.1 42.2 0.1 39.9 Ni_(0.62)Nb_(0.34)Ce_(0.04)O_(x) 14.7 81.6 14.581.5 14.4 81.5 Ni_(0.62)Ta_(0.34)Ce_(0.04)O_(x) 13.9 82.3 13.2 82.2 12.782.1 Ni_(0.76)Nb_(0.17)Er_(0.06)O_(x) 11.4 84.5 11.5 84.3 11.4 84.2Ni_(0.68)Ta_(0.25)Dy_(0.07)O_(x) 11.8 82.7 11.7 82.3 11.8 82.4Ni_(0.60)Nb_(0.19)Ta_(0.18)Sm_(0.03)O_(x) 14.1 82.8 13.7 82.2 13.7 82.4Ni_(0.64)Nb_(0.34)Pr_(0.02)O_(x) 13.7 82.9 12.7 81.0 12.8 81.4 blank 0.144.0 0.1 43.2 0.1 44.8 Ni_(0.63)Nb_(0.37)O_(x) 10.4 86.1 9.9 85.3 10.185.6 Ni_(0.51)Ta_(0.42)Zr_(0.07)O_(x) 12.9 82.3 12.5 82.0 12.6 82.1Ni_(0.73)Ti_(0.27)O_(x) 10.6 83.7 10.1 83.7 9.6 83.6Ni_(0.58)Ta_(0.34)Gd_(0.07)O_(x) 9.0 83.1 8.5 82.5 8.5 82.7Ni_(0.68)Nb_(0.24)Gd_(0.08)O_(x) 12.5 76.5 11.6 74.0 11.7 74.6Ni_(0.80)Nb_(0.19)Sb_(0.01)O_(x) 11.9 85.5 11.2 85.0 11.1 85.3 Part B2blank 0.1 40.0 0.1 40.6 0.1 41.1 Ni_(0.82)Nb_(0.14)Sb_(0.04)O_(x) 9.582.3 8.6 81.0 8.9 81.7 Ni_(0.60)Nb_(0.39)Sb_(0.01)O_(x) 16.0 83.4 15.482.9 15.5 83.2 Ni_(0.72)Nb_(0.27)Bi_(0.01)O_(x) 14.4 85.9 13.6 85.2 14.185.5 Ni_(0.73)Ta_(0.25)Bi_(0.02)O_(x) 9.8 85.7 8.9 85.5 9.3 85.7Ni_(0.63)Nb_(0.33)Yb_(0.04)O_(x) 12.6 82.2 10.8 80.4 12.0 81.3Ni_(0.59)Ta_(0.37)Yb_(0.04)O_(x) 6.2 85.1 5.4 85.0 5.9 85.0 blank 0.148.6 0.1 47.5 0.1 47.1 Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) 14.6 78.1 12.772.3 13.5 73.6 Ni_(0.71)Nb_(0.27)Sb_(0.02)O_(x) 14.2 73.4 11.4 62.3 12.364.8 Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) 12.4 78.4 10.2 70.3 10.8 73.1Ni_(0.63)Nb_(0.19)Ta_(0.18)O_(x)/TiO₂ 6.1 89.0 4.9 89.2 5.3 89.2Ni_(0.71)Nb_(0.27)Sb_(0.02)O_(x) 9.6 76.8 7.9 71.4 8.8 74.1Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) 17.0 85.6 16.0 85.4 17.6 85.9 blank 0.147.9 0.1 47.3 0.1 47.8 Ni_(0.74)Nb_(0.08)Ta_(0.17)Ce_(0.01)O_(x) 15.784.7 15.3 84.3 15.5 84.2 Ni_(0.75)Nb_(0.24)Ce_(0.01)O_(x) 18.6 86.3 18.286.1 18.4 86.3 Ni_(0.53)Ta_(0.40)Gd_(0.07)O_(x) 16.1 77.3 14.7 74.4 15.075.2 Ni_(0.74)Nb_(0.08)Ta_(0.17)Ce_(0.01)O_(x) 16.0 85.3 14.3 84.8 14.883.5 Ni_(0.74)Ta_(0.22)Yb_(0.04)O_(x) 17.8 85.1 16.6 84.7 17.4 84.9Ni_(0.65)Ta_(0.36)Bi_(0.01)O_(x) 14.9 82.9 12.6 83.0 14.4 83.7400 Hour Lifetime Test

In the 400 hour lifetime test, forty-eight different Ni(Nb, Ta, Ti)(Sm,Sn, Co, Cs, Sb, Ag)(Mg, Ca, Li) oxide catalysts were prepared byprecipitation using the metal salt precursors substantially as describedin earlier examples herein. The various catalyst compositions,post-precipitation treatment (if any) and calcination conditions areindicated in Table 26C.

The forty-eight catalysts of Table 26C (˜50 mg) were screenedsimultanteously in the 48-channel parallel fixed bed reactor foroxidative ethane dehydrogenation at 275° C. with ethane:oxygen flow of0.42:0.033 seem. Table 26D summarizes the amount of catalyst screened,as well as the ethane conversion (C) and ethylene selectivity (S) foreach of the catalysts, measured after various times during the test.These data show that, after 48 hours on stream, the 48 catalysts lost,on average, less than about 13% in conversion and less than about 2% inselectivity. Several of the catalysts had no substantial loss ofactivity or selectivity over the 400 hour test. FIGS. 2A and 2B showethane conversion and ethylene selectivity data versus time on streamduring the 400% hour lifetime test for Ni_(0.75)Ta_(0.28)Sn_(0.03)O_(x)(FIG. 2A) and Ni_(0.71)Nb_(0.27)Co_(0.02)O_(x) (FIG. 2B).

TABLE 26C Catalyst composition, library reference #, and preparationmethods for catalysts screened in 400 hour lifetime test. Library #Composition Remarks* (1,1) 16693.1ANi_(0.68)Nb_(0.10)Ti_(0.10)Ta_(0.10)Sm_(0.02)O_(x) 5/320/8/air (1,2)16693.1B Ni_(0.68)Nb_(0.10)Ti_(0.10)Ta_(0.10)Sm_(0.02)O_(x) PGS, >300 μm(1,3) 16693.1C Ni_(0.68)Nb_(0.10)Ti_(0.10)Ta_(0.10)Sm_(0.02)O_(x)PGS, >150 < 300 μm (1,4) 16693.2Ni_(0.68)Nb_(0.10)Ti_(0.10)Ta_(0.10)Sm_(0.02)O_(x) 5/320/8/N₂ (1,5)16693.3 Ni_(0.68)Nb_(0.10)Ti_(0.10)Ta_(0.10)Sm_(0.02)O_(x)5/320/8/air&5/320/8/H₂/Ar (1,6) 16693.4Ni_(0.68)Nb_(0.10)Ti_(0.10)Ta_(0.10)Sm_(0.02)O_(x) 5/320/8/H₂/Ar (2,1)16693.5 Ni_(0.68)Nb_(0.10)Ti_(0.10)Ta_(0.10)Sm_(0.02)O_(x)5/320/8/N₂&5/320/8/air (2,2) 16693.6Ni_(0.68)Nb_(0.10)Ti_(0.10)Ta_(0.10)Sm_(0.02)O_(x)5/320/8/H₂/Ar&5/320/8/air (2,3) 16777.31 Ni_(0.75)Nb_(0.25)O_(x)5/320/8/air (2,4) 16777.14 Ni_(0.66)Nb_(0.34)O_(x) 5/320/8/air (2,5)16777.35 Ni_(0.71)Nb_(0.26)Sm_(0.03)O_(x) 5/320/8/air (2,6) 16777.53Ni_(0.71)Nb_(0.26)Sm_(0.03)O_(x) 5/320/8/air (3,1) 16467.54Ni_(0.67)Nb_(0.32)Sn_(0.01)O_(x) 5/320/8/air (3,2) 16469.52Ni_(0.75)Ta_(0.28)Sn_(0.03)O_(x) 5/320/8/air (3,3) 16469.64Ni_(0.62)Ta_(0.37)Sn_(0.01)O_(x) 5/320/8/air (3,4) 16505.53Ni_(0.75)Zr_(0.23)Sn_(0.02)O_(x) 5/320/8/air (3,5) 16470.31Ni_(0.85)Ti_(0.13)Sn_(0.02)O_(x) 5/320/8/air (3,6) 16470.53Ni_(0.67)Ti_(0.31)Sn_(0.02)O_(x) 5/320/8/air (4,1) 16470.63Ni_(0.65)Ti_(0.32)Sn_(0.03)O_(x) 5/320/8/air (4,2) 16650.14ANi_(0.68)Nb_(0.10)Ti_(0.10)Ta_(0.10)Sm_(0.02)O_(x) 5/320/8/air (4,3)16650.14B Ni_(0.68)Nb_(0.10)Ti_(0.10)Ta_(0.10)Sm_(0.02)O_(x) 5/320/8/air(4,4) 16650.42 Ni_(0.68)Nb_(0.10)Ti_(0.10)Ta_(0.10)Sm_(0.02)O_(x)5/320/8/air (4,5) 11525 Ni_(0.63)Nb_(0.19)Ta_(0.18)O_(x) 5/400/8/air(4,6) 16610.3 Ni_(0.63)Nb_(0.19)Ta_(0.18)O_(x) 5/320/8/N₂ (5,1) 16365.31Ni_(0.85)Nb_(0.14)Co_(0.01)O_(x) 5/320/8/air (5,2) 16365.42Ni_(0.78)Nb_(0.20)Co_(0.02)O_(x) 5/320/8/air (5,3) 16365.53Ni_(0.71)Nb_(0.27)Co_(0.02)O_(x) 5/320/8/air (5,4) 16298.11Ni_(0.75)Nb_(0.22)Sm_(0.03)O_(x) 5/320/8/air (5,5) 16298.13Ni_(0.74)Nb_(0.21)Sm_(0.03)Cs_(0.02)O_(x) 5/320/8/air (5,6) 16298.41Ni_(0.75)Nb_(0.21)Sm_(0.03)Sb_(0.01)O_(x) 5/320/8/air (6,1) 16298.42Ni_(0.74)Nb_(0.21)Sm_(0.03)Sb_(0.02)O_(x) 5/320/8/air (6,2) 16298.71Ni_(0.74)Nb_(0.21)Ti_(0.02)Sm_(0.03)O_(x) 5/320/8/air (6,3) 16297.11Ni_(0.67)Ti_(0.30)Sm_(0.03)O_(x) 5/320/8/air (6,4) 16297.21Ni_(0.66)Ti_(0.30)Sm_(0.03)Mg_(0.01)O_(x) 5/320/8/air (6,5) 16297.24Ni_(0.64)Ti_(0.30)Sm_(0.03)Mg_(0.03)O_(x) 5/320/8/air (6,6) 16297.33Ni_(0.65)Ti_(0.30)Sm_(0.03)Ca_(0.02)O_(x) 5/320/8/air (7,1) 16297.83Ni_(0.62)Ti_(0.28)Ta_(0.07)Sm_(0.03)O_(x) 5/320/8/air (7,2) 16160.14Ni_(0.51)Nb_(0.14)Ti_(0.19)Ta_(0.15)O_(x) 5/320/8/air (7,3) 16160.43Ni_(0.58)Nb_(0.15)Ti_(0.11)Ta_(0.16)O_(x) 5/320/8/air (7,4) 16790.13Ni_(0.55)Ta_(0.44)Ag_(0.01)O_(x) 5/320/8/air (7,5) 16790.23Ni_(0.63)Ta_(0.36)Ag_(0.01)O_(x) 5/320/8/air (7,6) 16790.36Ni_(0.71)Ti_(0.28)Ag_(0.01)O_(x) 5/320/8/air (8,1) 16685.32Ni_(0.60)Ta_(0.38)Co_(0.02)O_(x) 5/320/8/air (8,2) 16687.33Ni_(0.66)Ti_(0.33)Co_(0.01)O_(x) 5/320/8/air (8,3) 16687.43Ni_(0.65)Ti_(0.33)Co_(0.02)O_(x) 5/320/8/air (8,4) 16828.14Ni_(0.71)Nb_(0.27)Co_(0.02)O_(x) 5/320/8/air (8,5) 16828.34Ni_(0.70)Nb_(0.27)Co_(0.02)Li_(0.01)O_(x) 5/320/8/air (8,6) 16828.62Ni_(0.77)Nb_(0.20)Co_(0.02)Mg_(0.01)O_(x) 5/320/8/air *Calcinationconditions = ramp rate (° C./min)/level(° C.)/dwell time(h)/environment.*PGS = pressed, ground and sieved.

TABLE 26D Catalyst library reference #, sample mass (mg) and ethaneconversion (C) and ethylene selectivity (S) measured at various times onstream during screening in 400 hour lifetime test. Time on stream (hour)0.9 4.9 167.4 248.8 406.2 Mass C S C S C S C S C S Library # (mg) (%)(%) (%) (%) (%) (%) (%) (%) (%) (%) Part A 16693.1 50.2 13.1 89.3 12.889.5 10.9 88.9 10.7 88.1 11.8 87.0 16693.1 51.2 14.0 90.1 13.9 90.5 12.290.1 12.1 89.0 13.1 88.4 16693.1 50.8 14.1 90.2 14.2 90.3 12.7 90.2 12.489.0 13.2 87.7 16693.2 50.9 4.9 0.2 13.0 62.6 12.5 87.7 12.3 86.3 9.985.9 16693.3 51.0 12.0 86.7 13.4 89.1 11.8 88.3 11.6 87.1 12.0 86.516693.4 50.0 7.8 64.1 10.9 84.6 9.4 86.6 9.2 85.1 9.7 83.2 16693.5 50.412.9 90.0 12.6 89.4 11.2 88.2 10.4 87.5 11.3 85.8 16693.6 49.8 11.5 87.99.1 87.3 9.0 85.2 8.7 84.3 9.2 82.9 16777.31 48.0 14.2 90.1 14.2 90.212.9 90.2 12.7 89.7 13.4 88.4 16777.14 53.6 15.0 90.6 15.0 90.9 13.089.4 12.6 88.7 11.8 88.3 16777.35 50.7 14.3 90.3 14.3 90.5 12.8 89.712.4 89.2 12.9 88.3 16777.53 48.0 14.8 90.5 14.5 90.6 12.7 89.8 12.489.0 13.0 87.4 16467.54 50.0 14.7 91.9 14.9 92.0 13.1 90.8 12.2 90.212.1 88.8 16469.52 52.0 15.5 92.1 15.0 91.9 14.1 92.1 14.1 91.9 15.191.7 16469.64 48.0 15.9 92.6 15.9 92.6 12.9 92.1 12.4 91.7 12.5 90.716505.53 52.6 12.8 86.5 12.7 86.3 11.3 84.4 9.9 83.8 9.3 83.3 Part B16470.31 51.0 13.2 87.8 12.9 87.4 11.0 85.3 10.6 84.8 11.1 84.3 16470.5348.7 16.1 92.6 15.5 92.7 14.6 92.7 14.6 92.5 11.4 91.8 16470.63 51.015.4 92.3 15.6 92.4 13.5 92.2 13.8 91.9 13.8 90.7 16650.14 49.1 14.490.8 14.0 90.8 12.1 89.2 11.7 88.4 12.1 87.4 16650.14 22.5 11.3 88.911.0 88.5 8.7 86.5 8.3 85.6 8.5 84.0 16650.42 54.8 14.9 90.3 14.6 90.611.9 89.7 10.7 89.0 12.3 88.4 11525 54.3 5.7 86.8 5.7 87.1 5.0 86.3 4.885.5 4.7 84.9 16610.3 52.0 15.4 91.5 14.8 91.9 12.2 91.6 12.3 91.1 10.489.9 16365.31 50.0 14.9 91.8 14.8 91.9 13.4 92.5 13.8 92.6 14.4 91.916365.42 50.2 15.1 91.7 15.2 91.9 14.6 92.5 14.6 92.3 15.5 91.9 16365.5349.8 15.3 91.4 15.5 91.5 14.5 92.0 14.6 91.6 15.2 90.4 16298.11 50.415.1 90.9 14.7 90.9 13.3 90.7 12.3 90.4 12.9 89.6 16298.13 50.0 15.391.3 15.2 91.3 14.2 91.1 14.2 91.0 14.5 90.4 16298.41 50.1 14.8 91.413.7 91.3 12.8 91.3 10.3 90.8 10.2 92.4 16298.42 49.8 15.5 92.3 15.392.4 13.6 92.9 14.0 92.5 14.2 91.6 16298.71 50.4 14.6 90.8 14.7 90.913.5 90.3 12.6 89.6 13.8 88.3 16297.11 49.6 14.2 91.8 15.7 91.9 14.091.8 14.2 91.3 14.5 90.0 16297.21 49.6 15.7 91.7 15.4 91.9 13.8 91.413.1 91.0 12.8 90.3 16297.24 49.7 15.5 91.7 15.3 91.9 14.0 91.2 13.890.8 13.9 89.9 16297.33 49.9 15.8 91.4 15.4 91.4 13.5 91.4 12.9 91.012.7 91.5 16297.83 49.6 15.8 91.1 15.2 91.5 12.9 91.0 13.1 90.3 12.988.5 16160.14 49.9 15.0 92.1 15.0 92.2 11.6 90.4 10.4 89.8 10.9 88.716160.43 50.1 15.0 92.1 13.7 92.0 11.6 90.4 11.4 89.9 11.4 88.6 16790.1350.0 14.7 91.6 14.4 91.7 11.6 90.3 11.3 90.0 11.3 89.6 16790.23 50.214.8 91.8 14.4 91.9 11.2 90.6 11.0 90.5 10.8 90.0 16790.36 50.2 15.290.8 14.8 91.2 12.5 90.4 12.6 91.2 12.2 90.3 16685.32 49.9 14.3 91.314.2 91.4 11.0 90.5 10.5 89.8 9.8 88.4 16687.33 49.5 13.5 91.0 15.2 91.213.9 90.5 12.8 89.9 13.7 88.3 16687.43 49.9 15.1 90.9 15.1 91.3 14.090.9 13.7 90.3 14.0 88.6 16828.14 50.2 15.1 90.5 15.0 90.8 13.8 90.913.5 90.6 13.9 89.8 16828.34 49.7 15.0 90.0 14.9 90.3 13.5 89.1 13.388.3 13.3 86.9 16828.62 50.6 14.8 91.2 14.0 91.4 13.3 91.7 12.8 91.913.6 91.7

Example 27 ODHE Over Ni(Nb, Ta, Ti, Zr)(Ce, Dy, Er, Nd, Sm, Yb, Pr, Gd,Sb, Bi) Oxide Catalysts with Ethylene Co-Feed

Catalyst compositions comprising various Ni(Nb, Ta, Ti, Zr)(Ce, Dy, Er,Nd, Sm, Yb, Pr, Gd, Sb, Bi) oxides were prepared as described inconnection with Example 26 (see Table 26A), and screened in the parallelfixed bed reactor for oxidative dehydrogenation with an ethane andethylene cofeed. Specifically, these catalysts were screened at 300° C.with an ethane (49.5%) and ethylene (50.5%) mixed feed at a ratio ofethane/ethylene mixed feed:nitrogen:oxygen was 0.42:0.54:0.088 sccm.

Table 27A shows the catalyst compositions, the sample mass thereofscreened, the amount of ethane loss/ethylene gain resulting from thereaction, and the calculated ethylene selectivity of the reaction. Thesedata demonstrate that the oxydehydrogenation activity of the catalystsare not substantially product inhibited, and that ethane dehyrogenationcan be effected using feed streams having ˜50% ethylene product.

TABLE 27A Ethane loss, ethylene gain and ethylene selectivity for amixed feed (ethane (49.5%) and ethylene (50.5%)) screen in the parallelfixed bed reactors. Test condition: (C₂H₄/C₂H₆):N₂:O₂ flow of0.42:0.54:0.088 sccm at 300° C. Ethylene Ethane Ethylene Mass Gain lossSelectivity Catalyst (mg) (%) (%) (%) Part A 1 Ni_(0.86)Ta_(0.14)O_(x)49.4 5.6 −7.9 59.9 2 Ni_(0.65)Ta_(0.31)Ce_(0.04)O_(x) 50.0 2.5 −5.8 38.03 Ni_(0.62)Nb_(0.19)Ta_(0.19)Ce_(0.01)O_(x) 50.4 0.4 −3.3 11.4 4Ni_(0.73)Ta_(0.24)Dy_(0.03)O_(x) 50.5 0.5 −3.8 10.7 5Ni_(0.68)Nb_(0.25)Dy_(0.07)O_(x) 49.8 2.0 −5.0 35.0 6Ni_(0.68)Nb_(0.26)Er_(0.06)O_(x) 49.8 2.8 −5.8 42.3 7 Blank 1.0 2.1−1.8 * 8 Ni_(0.62)Nb_(0.38)O_(x) 49.2 3.2 −6.0 46.0 9Ni_(0.71)Ta_(0.23)Nd_(0.06)O_(x) 49.6 0.8 −4.0 16.9 10Ni_(0.63)Nb_(0.34)Sm_(0.03)O_(x) 50.4 1.0 −4.5 19.9 11Ni_(0.54)Ta_(0.45)Sm_(0.01)O_(x) 49.5 2.0 −4.6 38.0 12Ni_(0.72)Ti_(0.28)O_(x) 50.0 2.7 −5.5 43.5 13Ni_(0.66)Ti_(0.29)Yb_(0.05)O_(x) 49.5 5.0 −7.3 58.5 14 blank 1.0 0.8−0.7 * 15 Ni_(0.62)Nb_(0.34)Ce_(0.04)O_(x) 42.6 −0.7 −2.9 0.0 16Ni_(0.62)Ta_(0.34)Ce_(0.04)O_(x) 47.6 −0.9 −2.5 0.0 17Ni_(0.76)Nb_(0.17)Er_(0.06)O_(x) 45.0 1.0 −3.1 27.3 18Ni_(0.68)Ta_(0.25)Dy_(0.07)O_(x) 44.2 2.1 −4.0 45.4 19Ni_(0.60)Nb_(0.19)Ta_(0.18)Sm_(0.03)O_(x) 45.6 5.3 −6.9 64.7 20Ni_(0.64)Nb_(0.34)Pr_(0.02)O_(x) 48.1 2.7 −5.0 46.8 21 blank 1.0 −1.00.8 * 22 Ni_(0.63)Nb_(0.37)O_(x) 45.9 −0.2 −1.9 0.0 23Ni_(0.51)Ta_(0.42)Zr_(0.07)O_(x) 44.5 2.5 −4.6 46.4 24Ni_(0.73)Ti_(0.27)O_(x) 45.8 1.3 −3.4 34.6 25Ni_(0.58)Ta_(0.34)Gd_(0.07)O_(x) 45.6 3.7 −4.9 65.2 26Ni_(0.68)Nb_(0.24)Gd_(0.08)O_(x) 55.2 2.7 −4.9 47.5 27Ni_(0.80)Nb_(0.19)Sb_(0.01)O_(x) 48.6 0.6 −2.8 19.9 Part B 28 blank 1.0−1.5 1.3 * 29 Ni_(0.82)Nb_(0.14)Sb_(0.04)O_(x) 49.6 1.5 −3.2 40.9 30Ni_(0.60)Nb_(0.39)Sb_(0.01)O_(x) 51.8 2.4 −5.2 40.5 31Ni_(0.72)Nb_(0.27)Bi_(0.01)O_(x) 54.7 5.1 −6.8 63.6 32Ni_(0.73)Ta_(0.25)Bi_(0.02)O_(x) 50.0 1.9 −3.5 47.9 33Ni_(0.63)Nb_(0.33)Yb_(0.04)O_(x) 41.1 0.5 −3.0 14.5 34Ni_(0.59)Ta_(0.37)Yb_(0.04)O_(x) 47.1 −0.7 −1.2 0.0 35 blank 1.0 −0.40.3 * 36 Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) 48.3 2.6 −5.1 44.1 37Ni_(0.71)Nb_(0.27)Sb_(0.02)O_(x) 49.1 6.0 −8.0 64.1 38Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) 49.3 2.7 −4.8 49.3 39Ni_(0.63)Nb_(0.19)Ta_(0.18)O_(x)/TiO₂ 145.9 −1.0 −0.8 0.0 40Ni_(0.71)Nb_(0.27)Sb_(0.02)O_(x) 51.5 −0.1 −2.0 0.0 41Ni_(0.65)Nb_(0.33)Ce_(0.02)O_(x) 49.7 2.3 −4.9 41.1 42 blank 1.0 −0.10.1 * 43 Ni_(0.74)Nb_(0.08)Ta_(0.17)Ce_(0.01)O_(x) 50.0 5.0 −7.2 59.3 44Ni_(0.75)Nb_(0.24)Ce_(0.01)O_(x) 50.2 3.2 −6.1 46.1 45Ni_(0.53)Ta_(0.40)Gd_(0.07)O_(x) 48.9 0.6 −4.2 13.3 46Ni_(0.74)Nb_(0.08)Ta_(0.17)Ce_(0.01)O_(x) 50.9 0.3 −3.5 8.9 47Ni_(0.74)Ta_(0.22)Yb_(0.04)O_(x) 50.7 2.1 −5.1 35.6 48Ni_(0.65)Ta_(0.36)Bi_(0.01)O_(x) 50.4 2.3 −4.9 41.1

Example 28 ODHE Over NiNbTa Oxide Catalyst with Multi-Stage Fixed BedReactor and Multiple Oxygen Feed

A NiNbTa oxide catalyst, Ni_(0.63)Nb_(0.19)Ta_(0.18)O_(x), prepared fromnickel nitrate, niobium oxalate and tantalum oxalate by precipitationwith tetramethylammonium hydroxide and with a maximum calcinationtemperature of 320° C. was screened in a three-stage fixed bed reactorhaving multiple oxygen feeds, substantially as shown and described inconnection with FIG. 1B.

Briefly, about 50 mg of the catalyst was loaded into each of the reactorstages. Ethane, oxygen and nitrogen were fed as initial feed to thefirst stage of the multi-stage reactor, wherein ethane was oxidativelydehydrogenated to form ethylene. The exhaust from the first stage wasfed to the second stage, together with additional oxygen and nitrogenfeed, and further oxidative dehydrogenation of ethane was effected inthe second stage. Similarly, exhaust from the second stage was fed tothe third stage, together with additional oxygen and nitrogen feed, andfurther oxidative dehydrogenation of ethane was effected in the thirdstage. The reaction exhaust from the third stage was analyzed by gaschromatograph.

Nine different experimental cases were considered with variations in (1)the relative flowrates of nitrogen:oxygen:ethane in the initial(first-stage) feed, (2) the relative flowrates of nitrogen:oxygen usedas additional feed in the second and third stages, and/or (3) thereaction temperatures of the three reaction zones (300° C. or 275° C.).

For comparison, the NiNbTa oxide catalyst was also screened, in each ofthe nine experimental cases, under similar reaction conditions in asingle-stage, single-feed fixed bed reactor, substantially as shown anddescribed in connection with FIG. 1A.

Table 28A shows the reaction temperature, amount of catalyst, initialfeed rates (sccm of nitrogen:oxygen:ethane), additional feed rates (sccmof nitrogen:ethane), and performance data (conversion, selectivity) foreach of the nine different experimental cases shows—for the multi-stagereactor and the single-stage reactor configurations. These datademonstrate that overall ethane conversion can be substantially improved(e.g., C of not less than about 30% C, and ranging from about 30% toabout 45%) while maintaining relatively high ethylene selectivities(e.g., S of not less than about 70% S, and ranging from about 70% toabout 85%).

TABLE 28A Ethane conversion and ethylene selectivity forNi_(0.63)Nb_(0.19)Ta_(0.18)O_(x) in multi- stage and single-stagereactor configurations at various relative flowrates and temperatures.Reactor Initial feed addition feed Configu- Reaction mass N2:O2:C2H6N2:O2 ration T (C) (mg) (sccm) (sccm) C(%) S(%) Part A SF 300 C 52.90.32:0.088:0.42 n/a 18.2 85.4 Case I MF1 300 C 51.6 0.32:0.088:0.42 MF2300 C 49.0 0.32:0.088 MF3 300 C 51.4 0.32:0.088 33.6 74.5 SF 300 C 52.90.25:0.066:0.42 n/a 17.4 87.7 Case II MF1 300 C 51.6 0.25:0.066:0.42 MF2300 C 49.0 0.25:0.066 MF3 300 C 51.4 0.25:0.066 32.0 76.9 SF 300 C 52.90.16:0.044:0.42 n/a 16.5 90.8 Part B Case III MF1 300 C 51.60.16:0.044:0.42 MF2 300 C 49.0 0.16:0.044 MF3 300 C 51.4 0.16:0.044 31.181.3 SF 300 C 52.9 0.082:0.022:0.42 n/a 11.4 93.6 Case IV MF1 300 C 51.60.082:0.022:0.42 MF2 300 C 49.0 0.082:0.022 MF3 300 C 51.4 0.082:0.02226.1 85.8 SF 300 C 52.9 0.16:0.044:0.208 n/a 22.0 85.9 Case V MF1 300 C51.6 0.16:0.044:0.208 MF2 300 C 49.0 0.16:0.044 MF3 300 C 51.40.16:0.044 44.6 73.9 SF 300 C 52.9 0.082: n/a 18.2 91.2 0.022:0.208 CaseVI MF1 300 C 51.6 0.082: 0.022:0.208 MF2 300 C 49.0 0.082:0.022 MF3 300C 51.4 0.082:0.022 39.3 78.4 SF 300 C 52.9 0.041: n/a 12.1 89.90.011:0.208 Case VII MF1 300 C 51.6 0.041: 0.011:0.208 MF2 300 C 49.00.041:0.011 MF3 300 C 51.4 0.041:0.011 29.0 84.8 SF 275 C 52.90.206:0.055:1.04 n/a 7.6 93.1 Case VIII MF1 275 C 51.6 0.206:0.055:1.04MF2 275 C 49.0 0.206:0.055 MF3 275 C 51.4 0.206:0.055 15.8 86.7 SF 275 C52.9 0.082:0.022:0.42 n/a 10.7 93.7 Case IX MF1 275 C 51.60.082:0.022:0.42 MF2 275 C 49.0 0.079:0.021 MF3 275 C 51.4 0.079:0.02123.2 86.0 SF = single feed; MF1 = multi-feed, 1^(st) stage; MF2 =multifeed, 2^(nd) stage; MF3 = multifeed, 3^(rd) stage; C = ethaneconversion; S = ethylene selectivity.

In light of the detailed description of the invention and the examplespresented above, it can be appreciated that the several objects of theinvention are achieved.

The explanations and illustrations presented herein are intended toacquaint others skilled in the art with the invention, its principles,and its practical application. Those skilled in the art may adapt andapply the invention in its numerous forms, as may be best suited to therequirements of a particular use. Accordingly, the specific embodimentsof the present invention as set forth are not intended as beingexhaustive or limiting of the invention.

1. A method for preparing a C₂ to C₄ alkene or a substituted C₂ to C₄alkene from the corresponding C₂ to C₄ alkane or substituted C₂ to C₄alkane, the method comprising providing a reaction zone comprising thecorresponding C₂ to C₄ alkene or substituted C₂ to C₄ alkene in a molarconcentration of at least 10%, relative to total moles of hydrocarbonand a catalyst comprising Ni, a Ni oxide, a Ni salt or mixtures thereof,feeding a C₂ to C₄ alkane or a substituted C₂ to C₄ alkane and a gaseousoxidant to the reaction zone, maintaining the reaction zone at atemperature ranging from about 200° C. to about 350° C., and oxidativelydehydrogenating the C₂ to C₄ alkane or substituted C₂ to C₄ alkane toform the corresponding C₂ to C₄ alkene or substituted C₂ to C₄ alkene inthe reaction zone under reaction conditions effective to convert the C₂to C₄ alkane or substituted C₂ to C₄ alkane to the C₂ to C₄ alkene orsubstituted C₂ to C₄ alkene, the C₂ to C₄ alkane or substituted C₂ to C₄alkane conversion being at least about 5%, and the C₂ to C₄ alkene orsubstituted C₂ to C₄ alkane selectivity being at least about 50%.
 2. Themethod of claim 1 wherein the C₂ to C₄ alkane or substituted C₂ to C₄alkane and the gaseous oxidant are co-fed to the reaction zone, themethod further comprising co-feeding a C₂ to C₄ alkene or substituted C₂to C₄ alkene corresponding to the C₂ to C₄ alkane or substituted C₂ toC₄ alkane to the reaction zone.
 3. The method of claim 1 wherein the C₂to C₄ alkane or substituted C₂ to C₄ alkane and the gaseous oxidant areco-fed to the reaction zone, the method further comprising exhausting aproduct stream comprising the corresponding C₂ to C₄ alkene orsubstituted C₂ to C₄ alkene and unreacted C₂ to C₄ alkane or substitutedC₂ to C₄ alkane from the reaction zone, and recycling at least a portionof the C₂ to C₄ alkene or substituted C₂ to C₄ alkene and unreacted C₂to C₄ alkane or substituted C₂ to C₄ alkane containing product stream tothe reaction zone.
 4. A method for preparing a C₂ to C₄ alkene or asubstituted C₂ to C₄ alkane from the corresponding C₂ to C₄ alkane orsubstituted C₂ to C₄ alkane the method comprising feeding a C₂ to C₄alkane or substituted C₂ to C₄ alkane to a first reaction zonecontaining a catalyst, the catalyst comprising a calcination product ofa composition comprising (i) a nickel-component selected from the groupconsisting of Ni, a Ni oxide, a Ni salt and mixtures thereof, the molarratio of the nickel-component ranging from about 0.5 to about 0.96, and(ii) an element or compound selected from the group consisting of Ti,Ta, Nb, Co, Hf, W, Y, Zn, Zr, Al, oxides thereof and salts thereof, ormixtures of such elements or compounds, co-feeding a gaseous oxidant tothe first reaction zone, dehydrogenating the C₂ to C₄ alkane orsubstituted C₂ to C₄ alkane to form the corresponding C₂ to C₄ alkene orsubstituted C₂ to C₄ alkene in the first reaction zone under reactionconditions effective to convert the C₂ to C₄ alkane or substituted C₂ toC₄ alkane to the C₂ to C₄ alkene or substituted C₂ to C₄ alkene,exhausting a product stream comprising the corresponding C₂ to C₄ alkeneor substituted C₂ to C₄ alkene and unreacted C₂ to C₄ alkane orsubstituted C₂ to C₄ alkane from the first reaction zone containing thecatalyst, feeding the C₂ to C₄ alkene or substituted C₂ to C₄ alkene andunreacted C₂ to C₄ alkane or substituted C₂ to C₄ alkane containingproduct stream from the first reaction zone to a second reaction zone,co-feeding a gaseous oxidant to the second reaction zone,dehydrogenating the C₂ to C₄ alkane or substituted C₂ to C₄ alkane toform the corresponding C₂ to C₄ alkene or substituted C₂ to C₄ alkene inthe second reaction zone.
 5. The method of claim 4, wherein theconcentration of oxygen in the first and second reaction zones iscontrolled to obtain an overall C₂ to C₄ alkane or substituted C₂ to C₄alkane conversion of at least about 5% and an overall C₂ to C₄ alkene orsubstituted C₂ to C₄ alkene selectivity of at least about 50%.
 6. Themethod of claim 4 wherein the molar concentration of oxygen in the firstand second reaction zones ranges from about 3% to about 20%, in eachcase relative to ethane.
 7. The method of claim 4 wherein the secondreaction zone comprises the corresponding C₂ to C₄ alkene or substitutedC₂ to C₄ alkene at a molar concentration of at least about 5%, relativeto total moles of hydrocarbon.
 8. The method of claim 4 wherein the C₂to C₄ alkane or substituted C₂ to C₄ alkane is oxidativelydehydrogenated in the second reaction zone to form the corresponding C₂to C₄ alkene or substituted C₂ to C₄ alkene with a C₂ to C₄ alkane orsubstituted C₂ to C₄ alkane conversion of at least about 5% and a C₂ toC₄ alkene or substituted C₂ to C₄ alkene selectivity of at least about50%.